UNIVERSITY  Of  CALIFORNIA 
LOS  ANGELES 


THE 


ELECTRIC  RAILWAY 


IX 


THEORY  AND  PRACTICE 


OSCAR    T.    CROSBY,   AND  LOUIS    BELL,   PH.D. 


SECOND   EDITION,   REVISED   AND   ENLARGED 


NEW   YORK 

THE   W.   J.   JOHNSTON    COMPANY,   LIMITED 

41  PARK  Row  (TIMES  BUILDING) 

1893 


COPYRIGHT,  1892  AND  1893,  BY 
THE   W.  J.  JOHNSTON  COMPANY,  LIMITED. 


TF 


c 

'/€:<?.  3 


PREFACE. 


IN  considering  so  widely  ramifying  a  subject  as  electri- 
cal traction  two  quite  distinct  methods  of  treatment  pre- 
sent themselves — one  the  discussion  of  general  principles, 
methods,  and  results,  the  other  the  detailed  study  of  motors 
and  their  peculiarities,  the  specific  parts  of  the  general 
equipment  and  their  use  in  daily  work.  These  two  are 
mutually  exclusive  in  any  volume  of  finite  size.  Believing 
that  the  latter  course  would  soon  lead  us  into  the  mere 
allotment  of  a  graveyard  for  defunct  apparatus,  description 
of  which  would  be  less  interesting  than  a  collection  of  epi- 
taphs and  would  possess  but  casual  value  even  to  the  moral- 
^.,1  ist,  we  have  chosen  the  former  line  of  treatment. 

We  have  endeavored  to  present  both  the  elementary  theory 
**    of  the  subject  and  the  general  features  of  the  best  practice, 
<A\     describing  in  detail  particular   methods  and  forms  of   car 
N^     machinery  only  in  so  far  as  they  are  of  importance  in  illus- 
r^trating  the  broad  principles  on  which  they  depend.     Specific 
A    instructions  have  been  introduced,   however,   when,   in  the 
present  state  of  the  art,  they  seemed  necessary  to  a  fuller 
comprehension  of  the  subject  and  a  more  thorough  grasp  of 
modern  methods. 

We  have  not  ventured  to  forecast  the  future  of  the  trans- 
mission of  energy  to  moving  motors,  for  nothing  save 
prophecy  after  the  fact  could  be  equal  to  the  situation ;  but 
have  contented  ourselves  with  indicating  certain  paths  of  im- 
provement that  may  lead  to  important  results. 

i 

379414 


2  PREFACE. 

In  pursuing  this  policy  we  hope  and  believe  that  our  sins 
will  be  found  to  be  those  of  omission  rather  than  commission, 
and  that  the  reader  will  deal  gently  with  them,  as  well-nigh 
unavoidable  in  this  first  general  discussion  of  a  new  and 
important  branch  of  applied  science. 

Our  hearty  thanks  are  due  to  the  many  friends  who  have 
most  courteously  aided  us  in  the  preparation  of  this  volume 
by  freely  giving  information  of  every  sort,  and  particularly 
to  Prof.  Elihu  Thomson,  Mr.  Carl  Hering,  Mr.  W.  E.  Baker, 
Mr.  H.  I.  Bettis,  Mr.  Thomas  Pray,  Jr.,  and  Mr.  Theo.  Steb- 
bins,  for  most  valuable  favors  of  such  kind. 

OSCAR  T.  CROSBY. 
Louis  BELL. 


TABLE  OF  CONTENTS. 


PAGE 

PREFACE .  i 

CHAPTER   I. 
GENERAL  ELECTRICAL  THEORY,        .......       5 

CHAPTER   II. 
PRIME  MOVERS,  .        .        ...        .        .        .        .        .        .29 

CHAPTER   III. 
MOTORS  AND  CAR  EQUIPMENT, 64 

CHAPTER   IV. 
THE  LINE, 123 

CHAPTER   V. 
TRACK — CAR  HOUSES — SNOW  MACHINES, 147 

CHAPTER   VI. 
THE  STATION, 161 

CHAPTER   VII. 
THE  EFFICIENCY  OF  ELECTRIC  TRACTION 202 

CHAPTER   VIII. 
STORAGE-BATTERY  TRACTION 230 

CHAPTER    TX. 

MISCELLANEOUS  METHODS  OF  ELECTRIC  TRACTION,        .        .        .  253 

3 


4  TABLE   OF   CONTENTS. 

CHAPTER  X. 

PAGE 

HIGH-SPEED  SERVICE,       ..'...••       «        .  273 

CHAPTER   XL 
COMMERCIAL  CONSIDERATIONS,  •  3°9 

CHAPTER  XII. 
HISTORICAL  NOTES .„..,..  333 


APPENDICES. 

APPENDIX   A. 
ELECTRIC  RAILWAY  vs.  TELEPHONE — DECISIONS 353 

APPENDIX   B. 
INSTRUCTIONS  TO  LINEMEN, 369 

APPENDIX   C. 
ENGINEER'S  LOG-BOOK, 381 

APPENDIX   D. 
CLASSIFICATION  OF  EXPENDITURES  OF  ELECTRIC  STREET  RAILWAYS,  382 

APPENDIX   E. 
CONCERNING  LIGHTNING  PROTECTION,  BY  PROF.  ELIHU  THOMSON,  389 

APPENDIX   F. 

MOTORS  WITH  BEVELED  GEAR  AND  SERIES-MULTIPLE  CONTROL  OF 
MOTORS, 403 

APPENDIX   G. 

METHOD   FOR  MEASURING  INSULATION  RESISTANCE  OF  OVERHEAD 

LINES, 405 


THE  ELECTRIC  RAILWAY 


THEORY  AND  PRACTICE. 


CHAPTER  I. 

GENERAL  ELECTRICAL  THEORY. 

IN  common  parlance  men  speak  of  electricity  as  "  that  mys- 
terious force;"  and  indeed  it  is  mysterious,  but  not  more  so 
than  the  "  force  of  gravity,"  "  capillary  attraction,"  "  chemical 
affinity,"  or  such  like  familiar  phenomena.  "Scratch  a  fact 
and  you  find  a  mystery"  is  a  homely  phrase  the  truth  of 
which  is  as  a  seal  of  bondage  upon  the  human  race. 

Two  portions  of  iron  attract  each  other  simply  by  virtue  of 
their  mass  (itself  a  word  impossible  to  define  absolutely) ,  and 
the  force  between  the  two  bodies  diminishes  as  the  square  of 
the  separating  distance  increases.  This  phenomenon  we  say  is 
explained  by  the  law  of  gravity.  But  why  does  the  force  vary 
inversely  as  the  square  of  the  distance  ?  Why  not  as  the  cube, 
or  the  fourth  power?  Why,  indeed,  does  it  vary  at  all? 
Why  is  there  attraction  or  force  at  any  distance  ?  Is  not  the 
whole  matter,  ultimately,  as  little  understood  as  the  fact  that 
under  certain  conditions  the  same  iron  bodies  may  exhibit  the 
action  of  another  force,  called  another  because  its  relation  to 
other  phenomena — its  law — is  different  from  that  of  gravi- 
tation? We  call  that  other  force  magnetic.  Its  law  seems  to 
be  somewhat  less  simple,  but  ultimately  is  not  more  mysteri- 
ous than  that  of  the  force  of  gravity. 

5 


6  THE   ELECTRIC    RAILWAY. 

In  furtherance  of  efforts  to  simplify  our  conceptions  of — that 
is,  our  working  hypotheses  for — all  the  operations  of  nature, 
it  is  convenient  to  consider: 

First,  that  all  bodies  of  appreciable  magnitude  are  com- 
posed of  minute  bodies  of  inappreciable  magnitude. 

Second,  that  these  smaller  bodies — atoms  or  molecules — are 
perpetually  in  motion. 

Third,  that  the  varying  states  of  any  body  as  to  hard- 
ness, mechanical  strain,  temperature,  light,  etc.,  correspond 
to  varying  modes  of  motion  of  the  constituent  molecules. 
These  may  change  their  paths,  their  velocities,  or  both,  or 
their  groupings. 

Fourth,  that  the  resultant  force  between  a  given  body  and 
the  surrounding  medium  will  generally  change  when  any 
change  occurs  in  the  motion  of  its  molecules.  The  change  of 
state  in  the  body  may  thus  be  recorded  by  corresponding 
change  in  a  sentient  organization,  such  as  the  human  being. 

It  seems  possible  to  conceive  that  all  differences  of  material 
in  the  universe  may  correspond  to  variations,  from  point  to 
point  in  space,  of  the  motion  of  particles  themselves  ho- 
mogeneous. 

As  the  very  nature  of  these  supposed  ultimate  particles  can- 
not be  accurately  conceived,  this  mechanical  conception  of 
the  universe  rises  up,  as  do  all  other  fundamental  concep- 
tions, from  an  inexplicable  mystery.  It  does,  however,  serve 
a  good  purpose  in  correlating  phenomena. 

Magnetism,  or  the  property  of  developing  magnetic  force, 
has  been  discovered  in  but  few  substances.  Iron,  nickel 
and  cobalt  show  this  property  in  specially  marked  degree.  Of 
these,  iron  and  its  compounds — steel  and  cast  iron — are  by 
far  the  most  important.  No  iron  can  be  said  to  be  wholly 
non-magnetic,  although  some  of  its  alloys  are  nearly  so. 

To  define  magnetism  completely  would  be  to  describe  in 
full  its  relations  to  other  phenomena.  These  are  not  all 
understood.  Expressions  have,  however,  been  reached  for 
the  chief  characteristics  of  magnetic  action. 

To-day  the  most  important  relation  of  magnetism  is  that 
with  the  flow  of  electricity.  This  latter  term,  like  magnetism, 
can,  of  course,  be  only  approximately  denned,  and  a  complete 


GENERAL  ELECTRICAL  THEORY.  7 

definition  cannot  be  made  without  a  lengthy  recitation  of  its 
characteristics.  We  will,  however,  be  helped  by  some  such 
formula  as  this :  There  is  said  to  be  a  flow  or  current  of  elec- 
tricity in  a  given  medium  when — due  to  an  initial  disturbance 
which  may  be  a  magnetic,  chemical,  frictional  or  thermal 
change — the  particles  of  that  medium  so  move  as  to  (i)  pro- 
duce the  sensation  called  heat,  or  (2)  light,  or  (3)  certain 
chemical  changes,  or  (4)  magnetic  change,  or  (5)  other  elec- 
trical flow,  and  (6)  finally — appealing  again  to  bodily  sensa- 
tion— the  peculiar  effect  experimentally  associated  with  the 
phenomenon  described. 

This  definition  may  seem  to  take  much  for  granted,  may 
seem  to  be  only  a  circular  reasoning,  but  substantially  all  defi- 
nitions found  themselves  on  things  taken  for  granted,  other- 
wise every  definition  would  be  a  complete  explanation  of  the 
universe. 

Such  a  mode  of  molecular  motion — a  current  of  electric- 
ity— may  be  produced  in  any  known  substance,  but  it  is  most 
readily  produced  in  the  metals  and  certain  liquids.  When 
the  disturbing  force  must  be  very  great  in  order  to  produce 
an  appreciable  electrical  effect  in  a  particular  medium,  that 
medium  is  called  an  insulator  or  non-conductor. 

The  earliest  method  of  producing  a  sustained  electrical  cur- 
rent was  that  familiar  even  to-day  in  primary  batteries.  In 
these  it  is  found  that  if  a  metal  be  brought  in  contact  with 
another  different  metal,  or  with  certain  non-metallic  bodies, 
and  both  be  then  immersed  in  a  fluid  producing  unequal 
chemical  reactions  upon  them,  a  current  of  electricity  will 
flow  across  the  surface  of  contact  between  the  two  bodies,  or 
along,  a  third  body  (as  a  wire)  if  it  be  a  conductor  and  joined 
to  the  two  immersed  bodies.  Zinc  has  been  found  to  be  gen- 
erally the  best  metal  for  use  in  batteries,  as  that  which  is  to  be 
most  acted  upon  by  the  fluid — usually  an  acid. 

A  primary  battery  is  very  convenient  and  useful  for  many 
cases  in  which  an  electric  current  is  desired.  When,  how- 
ever, the  supply  of  power  (or  current)  is  required  to  be  con- 
siderable the  method  is  expensive  to  a  prohibitory  degree,  as 
zinc  must  constantly  be  consumed  in  proportion  to  the  energy 
supplied  by  the  battery.  The  maximum  possible  supply  of 


8  THE    ELECTRIC   RAILWAY. 

energy  from  a  pound  of  zinc  is  about  1,808,000  foot-pounds. 
Zinc  usually  costs  about  six  cents  per  pound.  Hence  if  the 
energy  be  utilized  by  a  process  having  95  per  cent,  efficiency, 
the  cost  per  foot-pound  =  0.0000035  cent. 

The  maximum  possible  supply  of  energy  from  a  pound  of 
good  coal  is  about  1 1, 120,000  foot-pounds.  The  coal,  at  $5.00 
per  ton,  costs  then  0.25  cent  per  pound.  The  efficiency  of 
utilization  in  a  good  steam  plant  is  about  1 3  per  cent. ,  giving 
to  the  fly-wheel  about  1,445,600  foot-pounds  per  pound  of 
coal.  The  dynamos  of  modern  make  return  90  per  cent,  in 
electrical  energy  of  the  mechanical  energy  received  from  the 
fly-wheel  of  the  engine.  Hence  the  cost  per  foot-pound 
delivered  from  the  dynamos  =  .0000002  cent,  or  only  one 
seventeenth  part  of  the  cost  in  the  case  of  the  primary  battery. 

Ignorance  of  these  facts  has  resulted  in  the  wasteful 
expenditure  of  much  honest  effort  and  money. 

The  possibilities  in  the  matter  of  the  direct  production  of 
electrical  energy  from  heat  seem  to  be  worth  considering, 
and  some  day  may  hear  the  proclamation  of  a  success  that  will 
revolutionize  present  methods  in  electrical  work.  For  the 
present,  however,  the  familiar  steam  engine  or  water-wheel, 
connected  to  drive  an  electro-magnetic  machine,  is  the  only 
combination  fitted  to  produce  electrical  energy  for  general 
distribution  to  lamps  or  motors. 

(A)  Faraday  observed  some  sixty  years  ago  the  fact  that  if 
a  conductor,  say  a  loop  of  copper  wire,  be  moved  in  certain 
ways  in  the  neighborhood  of  a  magnet,  an  electrical  current 
is  caused  to  flow  in  the  loop.  (B)  It  was  further  estab- 
lished that  if  a  current  be  made  to  pass  around  a  magnetic 
body — as  when  a  piece  of  iron  is  surrounded  by  a  coil  carry- 
ing a  current — the  magnetic  action  in  the  body  would  be 
affected  thereby. 

These  two  facts  or  laws  are  involved  in  the  operation  of  all 
modern  dynamos.  The  armature  of  such  machines  consists 
of  a  number  of  conducting  loops,  the  circuit  of  which  is  made 
complete  through  the  brushes  and  any  wire  or  other  con- 
ductor to  the  ends  of  which  the  brushes  may  be  connected. 

For  simplicity  the  armature  is  represented  in  Fig.  i  as  a 
simple  loop.  When  rotation  of  this  loop  begins  under  the  ac- 


GENERAL  ELECTRICAL  THEORY. 


tion,  say,  of  a  steam  engine,  we  have  at  once  the  case  referred 
to  in  (A).  The  magnets  and  their  extensions,  called  the 
pole  pieces,  are  generally  of  wrought  or  cast  iron,  and  these 


FIG.  i.— DIAGRAM  OF  SIMPLE  DYNAMO. 


FIG.  2.— SHUNT  WOUND  DYNAMO 


substances  are  often,  loosely,  said  to  be  not  permanently  mag- 
netic, while  steel  is  credited  with  that  property.  But  in  fact 
these  field  magnets  are  always  slightly  magnetic.  They  thus 
create  around  them  a  "field  of  force,"  that  is,  a  region  in 
which  magnetic  force  may  be  shown  to  exist,  as  by  the  col- 
lection of  iron  filings  around  the  poles.  Assuming  some  unit 
of  force  which  need  not  here  be  defined,  the  strength  of  the 
field  is  conveniently  expressed  by  referring  to  the  number  of 
lines  (units)  of  force  passing  through  a  unit  area,  taken  at 
right  angles  to  the  direction  of  the  force,  as  shown  by  the  iron 
filings.  The  slightly  magnetized  pole  pieces  cause  a  few 
lines  of  force  to  traverse  the  space  within  which  the  armature 
revolves,  the  result  being  that  a  very  weak  current  flows  to 
one  of  the  brushes,  called  the  positive,  thence  through  the 


10  THE    ELECTRIC    RAILWAY. 

coils  around  the  magnets  and  returns  to  the  other,  the  nega- 
tive brush  By  virtue  of  the  flow  that  has  taken  place  around 
them,  the  magnets  become  (case  B)  more  strongly  magnetic, 
the  current  generated  by  and  in. the  armature  wires  becomes 
stronger,  and  so  there  goes  on  an  interactive,  cumulative 
effect  between  armature  current  and  magnetic  strength, 
until,  usually  in  about  20  to  30  seconds,  the  full  normal 
strength  of  the  magnet  has  been  attained.  If  the  current  be 
interrupted,  either  by  stopping  the  driving  engine  or  by 
breaking  the  circuit,  the  wrought  or  cast  iron  magnets  and 
pole  pieces  will  lose  all  the  strength  gained  from  the  flow  of 
current,  but  will  retain  enough  permanent  magnetism  to  start 
again  in  a  similar  cycle. 

If  all  the  electrical  energy  developed  by  the  armature  were 
expended  in  the  magnet  coils,  no  useful  outside  work  could 
be  done.  Two  methods  will  be  explained  by  which  the  mag- 
net coils  receive  the  necessary  exciting  current,  while  a  much 
larger  supply  is  provided  for  heating  a  carbon  to  incandes- 
cence, or  producing  rotation  in  a  motor  armature  which  will 
do  mechanical  work  on  any  machine  suitably  connected  :o  it 
by  belt  or  gears. 

In  Fig.  2  it  will  be  seen  that  starting  from  the  positive 
brush  two  paths  are  provided,  one  leading  around  the  mag- 
nets, the  other  through  a  lamp  and  a  second  armature,  repre- 
senting a  motor.  This  second  path  is  generally  called  the 
"  working  circuit. "  The  first  is  called  the  "  magnet  "  or  "  field  " 
circuit. 

In  any  conductor  there  is  found  to  be  a  certain  resistance 

to  the  flow  of  an  electric  current ;  for  any  given  substance  the 

resistance  is  found  to  increase  directly  as  the  increase  of 

length,  and  decrease  directly  as  the  increase  of  cross-section. 

The  relative  resistances  of  circuits  fed  from  the  same  source, 

as  in  Fig.  2,  can  thus  be  easily  regulated.     If  the  resistance 

of  the  magnet  coils  be  ten  times  that  of  the  working  circuit, 

the  latter  will  receive  ten  times  the  quantity  of  current  in  the 

rnner.     Instead  of  having  only  a  single  wire  for  each  of  the 

circuits,  there  may  be  any  number,  but  they  may  always 

magmed  as  forming  a  single  wire,  the  resistance  of  which 

st  equal  to  that  of  the  combination  of  wires ;  and  in  such  a 


GENERAL  ELECTRICAL  THEORY. 


I  I 


discussion  as  this  we  need  consider  only  this  representative 
wire. 

Looking  at  Fig.  3  it  is  seen  that  the  current  has  but  one 
path ;  leaving  the  positive  brush,  it  .passes  around  the  mag- 
nets, thence  to  the  outer  working  circuit,  and  returns  to  the 
negative  brush.  If  in  this  case  the  total  output  of  current  be 
the  same  as  in  the  previous  case,  the  number  of  turns  in  the 
magnet  coil  may  be  very  much  less  than  before,  the  magnet- 
izing effect  remaining  equal.  It  has  been  experimentally 
proved,  and  may  now  be  called  a  law,  that  the  magnetizing 
effects  of  different  coils  carrying  varying  currents  may  be 
compared  by  comparing  the  product  of  the  number  of  coils  by 
the  strength  of  the  current  flowing  through  them.  Thus  ten 
turns  of  wire  carrying  one  unit  (called  an  ampere)  of  current 
will  produce  the  same  effect  as  one  turn  carrying  ten  units — 


FIG.  3.— SERIES  WOUND  DYNAMO 


FIG.  4.— COMPOUND  WOUND  DYNAMO 


or  amperes.  One  hundred  turns  carrying  half  an  ampere 
(100  X  0.5  =  50)  will  produce  one-half  the  effect  of  fifty  turns 
carrying  two  amperes  (50X2  =  100)  and  thus  generally, 
multiply  the  number  of  turns  in  the  magnet  coils  by  the 


I2  THE   ELECTRIC   RAILWAY. 

number  of  amperes  flowing  through  those  coils,  and  the  prod- 
ucts formed  show  the  relative  magnetizing  effects  of  the 
respective  coils.  This  product  of  the  amperes  by  the  turns 
measures  what  may  be  called  the  magneto-motive  force. 

Referring  to  Figs.  2  and  3,  if  we  suppose  the  total  current 
to  be  the  same,  and  that  in  Fig.  2  only  one-tenth  of  the  total 
amount  goes  through  the  magnet  coils,  the  number  of  these 
coils,  for  equal  magnetization,  would  have  to  be  ten  times  as 
great  as  in  Fig.  3,  in  which  there  is  but  one  circuit,  contain- 
ing the  magnet  coils,  as  well  as  the  lamps  or  motors  for 
which  the  supply  is  given.  In  Fig.  2  the  work  of  the  exter- 
nal circuit  is  done  by  a  part  of  the  whole  current  generated 
(say  0.9)  flowing  under  the  whole  of  the  electrical  pressure 
between  brushes.  In  Fig.  3  the  external  work  is  done  by 
the  whole  of  the  current  flowing,  under  a  pressure  less  than 
that  existing  between  brushes  by  the  amount  required  to  force 
the  current  through  the  magnet  coils.  The  ratio  between  the 
energy  delivered  to  the  dynamo  and  the  useful  work  per- 
formed by  it  may  be  the  same  in  the  two  cases,  and  this  ratio 
is  called  the  "efficiency  "  of  the  dynamo. 

The  arrangement  shown  in  Fig.  2  constitutes  what  is 
known  as  a  "shunt  winding  "  for  a  dynamo,  that  of  Fig.  3  a 
"series  winding."  A  third  type,  Fig.  4,  called  a  " compound 

winding,"  results  from  a  combination  of  the  two part  of  the 

required  magnetizing  effect  (or  ampere  turns)  being  given  by 
a  shunt  coil,  and  part  by  a  series  coil.  The  use  of  the  word 
"  shunt "  as  an  electrical  term  results  from  an  easy  transition 
from  its  use  (more  general  in  England  than  in  America)  as  a 
railway  term  denoting  a  branch  or  siding. 

Any  conductor  carrying  a  portion,  not  the  whole,  of  a  cur- 
rent flowing  from  a  given  point  may  be  said  to  be  in 
1  shunt  "  relation  to  some  other  conductor  or  conductors.  The 
same  relation  is  sometimes  indicated  by  saying  that  the  con- 
ductors are  "in  parallel,"  "in  parallel  arc,"  "in  multiple,"  or 
Hiple  arc"  with  respect  to  each  other.  It  would  be 
best,  perhaps,  to  use  no  other  expression  than  "multiple." 
5,6?  show  various  relations  of  combined  conductors, 
i  speaking  of  the  quantity  of  electricity  flowing  in  a  con- 
*or  we  have  simply  used  a  popular  and  convenient  expres^ 


GENERAL  ELECTRICAL  THEORY.  13 

sion.  No  direct  dimensional  measurement  of  "  quantity  "  can 
be  had.  But  by  observing  that  in  one  case  a  current  separates 
a  certain  weight  of  water  into  its  constituent  elements,  while 
in  another  twice  or  three  times  the  weight  is  thus  decom- 
posed ;  that  now  one  ounce  of  silver  is  deposited  on  a  metal 


FIG.  5.—  RESISTANCES  IN  SERIES. 

surface,  and  again  two  or  three  ounces  ;  that  now  a  lamp  car- 
bon is  only  dull  red,  while  again  it  is  brilliantly  white  —  we 
are  brought  face  to  face  with  the  different  quantities  of  work 
performed,  and  are  forced  to  conclude  that  the  molecules 
themselves  of  the  conductor  have  different  quantities  of  the 


FIG.  6.— RESISTANCES  IN  MULTIPLE. 

energy  of  motion,  due  to  the  original  disturbing  forces  of 
different  magnitudes.  The  force  producing  the  molecular 
movement,  which  in  turn  presents  electrical  phenomena,  is 
called  an  "  electromotive "  force.  If  electromotive  forces 
emanating  from  different  sources  are  applied  to  a  conductor 


FIG.  7.— RESISTANCES  IN  SERIES  MULTIPLE. 


which  itself  remains  unchanged,  and  it  is  learned,  by  measur- 
ing their  effects,  that  currents  of  the  same  or  different 
strengths  flow  from  these  different  sources,  then  the  equality 
or  inequality  of  the  electromotive  forces  is  implied.  So,  if 
we  consider  the  flow  of  water  in  a  particular  section  of  pipe, 
we  judge  of  the  relative  pressures  causing  the  flow  by  noting 


1 4  THE   ELECTRIC   RAILWAY. 

its  quantity  or  measuring  the  work  it  can  do,  the  resistance 
to  flow— such  as  friction  on  the  walls  of  the  pipe — being- 
assumed  constant. 

Generally  it  will  be  readily  understood  that  the  quantity  of 
motion  produced  by  a  disturbing  force  acting  in  any  medium 
will  be  relatively  great  or  small  as  the  resistance  to  that  form 
of  motion  is  small  or  great ;  further,  whatever  the  resistance 
may  be,  if  it  be  constant  the  quantity  of  motion  will  be  greater 
as  the  force  becomes  greater.  In  electrics  this  relation 
may  be  expressed  thus:  The  current  flowing  in  any  circuit 
varies  inversely  as  the  resistance,  and  directly  as  the  electro- 
motive force  (usually  written  E.  M.  F.).  Adopting  a  system 
of  correlated  units,  if  the  E.  M.  F.  be  of  magnitude  expressed/ 
by  unity  and  likewise  the  resistance,  then  the  current  flowing 
will  be  unit  current.  If  the  E.  M.  F.  remain  the  same  and 


FIG.  8.— ELECTROMOTIVE  FORCES  IN  SERIES. 


the  resistance  become  0.5  or  2,  the  current  would  become 
twice  its  former  value,  or  half,  as  the  case  may  be.  If  the 
resistance  remain  the  same  and  the  E.  M.  F.  become  0.5 
or  2,  then  the  current  becomes  half  its  former  value,  or 
twice,  as  the  case  may  be.  Generally,  then,  it  appears  that 
we  may  write: 

Current  =  ~~~ ;  or  abbreviating.  C  =  | . 

This  relation  is  always  known,  from  the  man  who  demon- 
strated it,  as  Ohm's  law. 

The  specific  resistances  of   many  substances   (that  is,  the 

itances  of  bars  of  unit  length  and  cross-section),  expressed 

units  of  resistance,  have  been  carefully  tabulated. 

t  would  also  be  fair  to  assume  equality  of  electromotive 

s  in  different  cases  if  there  be  the  same  physical  arrange- 


GENERAL  ELECTRICAL  THEORY.  15 

ment  of  parts  in  the  generator.  Thus  a  particular  combina- 
tion of  zinc,  copper  and  acid,  if  applied  to  any  number  of  cir- 
cuits, may  reasonably  be  supposed  to  produce  the  same 
electromotive  force  in  all ;  observed  differences  in  the  quan- 
tity of  current  produced  would  then  fairly  be  attributable  to 
differences  of  resistance  in  the  various  circuits.  And,  again,  if 
two  similar  combinations  be  placed  in  the  same  circuit,  one 
following  the  other,  as  in  Fig.  8,  it  is  fair  to  assume  that  we 
have  twice  the  electromotive  force  that  would  be  given  by 
one  of  the  combinations  acting  alone ;  and  that  consequently 
we  would  have  twice  the  current  if  the  resistance  of  the  cir- 
cuit were  the  same  in  the  two  cases. 

Likewise,  if  we  make  two  similar  dynamos  and  run  them 
under  similar  conditions,  they  will  produce  equal  electro- 
motive forces.  As  to  the  force  developed  in  any  particular 
case,  experiment  shows  that  it  increases  with  the  number  of 
complete  changes  from  zero  to  maximum  in  the  number  of 
lines  of  magnetic  force  passing  through  the  looped  conductor 
of  the  armature  in  any  fixed  interval  of  time,  and  with  the 
magnitude  of  each  change.  It  follows  that  in  an  actual 
dynamo,  increase  in  four  separate  elements  will  independently 
increase  the  electromotive  force  produced  in  its  armature,  (i) 
strength  of  magnetic  field,  (2)  area  of  revolving  loop,  (3) 
number  of  loops,  when  arranged  each  in  series  with  its 
neighbor,  (4)  velocity  of  rotation.  If  we  can  determine  ex- 
perimentally the  electromotive  force  produced  by  a  change  of 
one  line  of  force  through  the  loop  in  unit  time,  the  dynamo 
may  then  be  proportioned  to  produce  a  given  E.  M.  F. 

Concerning  the  strength  of  field — or  number  of  lines  of  mag- 
netic force  per  unit  area — it  has  already  been  explained  that 
the  force  called  magneto-motive  force,  producing  such  effects, 
increases  with  the  increase  of  ampere-turns  around  the  body 
of  the  magnetic  metal.  While  this  is  always  strictly  true,  it 
is  also  true,  as  in  all  other  cases  of  disturbing  forces,  that 
the  quantity  of  motion,  of  any  particular  kind,  depends  upon 
the  resistances  met,  as  well  as  the  original  forces  acting. 
Indeed,  the  relation  between  "  lines  of  force,"  magneto-motive 
force,  and  magnetic  resistance  may  be  expressed  in  terms  as 
simple  as  those  of  Ohm's  law.  Using  the  term  "  Induction  "  in 


j6  THE    ELECTRIC    RAILWAY. 

a  sense  analogous  to  that  in  which  "  Current "  is  used,  we 

may  write 

M.  M.  F.  M 


Induction  = 


Resistance'  R' 


All  substances  save  three   (iron,  nickel  and  cobalt)   have 
enormously  high  magnetic  resistance. 

Magnetic  action  takes  place  along  lines  connecting  one  pole 


N 


FIG.  O.-BAK  MAGNET. 

of  the  magnet  with  the  other,  and  the  resistance  to  magnetic 
action  along  such  lines  determines  the  "  strength  of  field  "  set 
up  by  a  given  magneto-motive  force. 

Thus  (Fig.  9)  in  case  of  the  straight  magnet  N  S  there  is 
a  long  air  space  between  N  and  S,  and  air  is  susceptible  to 
magnetic  action  only  in  a  very  low  degree.  We  may  then 
increase  the  strength  of  field  by  simply  bending  the  magnet 
into  a  U  shape,  thus  shortening  the  air  space  between  the 
poles,  without  change  in  the  dimensions  of  the  magnet  or  in 
the  number  of  ampere  turns  exciting  it.  An  armature  revolv- 
ing between  N'  S'  (Fig.  10)  would,  at  the  same  velocity,  gen- 
erate more  than  twice  the  E.  M.  F.  that 
it  would  if  placed  at  either  A  or  B  (Fig.  9) . 
Further,  an  armature  whose  wires  are 
wound  on  an  iron  core,  occupying  as  much 
as  possible  of  the  space  between  N  and  S, 
will  generate  in  each  coil  a  greater  E.  M. 
F.  at  same  speed  than  would  one  on  a 
non-magnetic  core,  since  the  total  resist- 
ance to  magnetic  action  is  less  in  the 
first  case  than  in  the  second. 

If,  starting  with  the  straight  magnet, 
we  not  only  bend  it  to  bring  the  ends  near  each  other,  but 
also  actually  shorten  the  magnet,  we  again  diminish  the 
total  resistance  in  the  magnetic  circuit,  and  with  the  same 
magneto-motive  force  obtain  more  "  lines  of  force  "  passing 
through  unit  area  from  N  to  S— or  we  may  again  diminish 
resistance  by  increasing  the  cross-section  of  the  magnet,  just 


N 


S' 


FIG.  10. -HORSESHOE 
MAGNET. 


GENERAL  ELECTRICAL  THEORY.  I/ 

as  we  would  decrease  resistance  to  an  electric  flow  by  using 
large  wires  instead  of  small  wires. 

It  might  seem  from  the  foregoing  remarks  that  any  desired 
strength  of  field  could  be  obtained  by  proportionate  increase 
of  magneto-motive  force  or  decrease  of  resistance.  But  un- 
fortunately experiment  has  shown  that  after  being  magnet- 
ized to  a  certain  degree,  even  iron  becomes  stubborn  as  air  or 
other  non-magnetic  bodies  to  any  increase  of  magnetism, 
however  high  we  may  urge  the  magneto-motive  force.  When 
magnetized  to  such  a  degree,  iron  is  said  to  be  "saturated." 
It  has  been  further  found,  as  might  be  expected,  that  in 
approaching  saturation  the  resistance  of  iron  to  further  action 
becomes  gradually  greater  until  it  becomes  as  great  as  air. 


20     25 

FIG.  n.— MAGNETIC  PRO 


•ERTIES  OF  VARIOUS  IRONS. 


Over  a  certain  range,  the  increase  of  magnetic  strength  in 
iron  seems  exactly  proportional  to  increase  of  the  magnetiz- 
ing ampere  turns,  but  beyond  that  range  this  strict  proportion 
disappears.  Thus  let  us  say  that  ten  ampere  turns  (often 
written  A-ts)  produce  a  magnetic  strength  denoted  by  unity. 
Twenty  ampere  turns  may  then  produce  a  strength  2,  but  in 
going  to  forty  we  may  find  the  strength  not  4  but  3  only, 
and  in  going  to  160  we  find  the  strength  barely  3.5,  and  so 


ig  THE   ELECTRIC    RAILWAY. 

i   until  a  point  is  reached  where  no  perceptible  increase  of 
str'eng  h  follows  from  any  increase  of  magneto-motive  force 
This  change  in  the  magnetic  resistance  of  different  kinds  of 
iron  is  best  shown  by  the  curves  (Fig.  1 1). 

On  the  horizontal  axis  are  shown  magneto-motive  forces 
increasing  from  left  to  right.  On  the  vertical  axis  are  shown 
the  corresponding  strengths  of  magnetization  produced  in 
various  materials  under  like  conditions.  If  the  iron  did  not 
increase  in  magnetic  resistance  the  E.  M.  F.  generated  in  an 
armature  would  increase  steadily  with  the  M.  M.  F.,  as  H 
does  very  nearly,  until  the  curves  turn  sharply  to  the  right- 
but  beyond  that  point  the  increase  of  E.  M.  F.  is  less,  rela- 
tively,  than  the  increase  of  M.  M.  F. 

The  general  principles  governing  the  design  of  dynamos 
and  motors  have  now  been  discussed. 

To  show  their  application,  let  us  suppose  that  it  is  desired 
to  construct  a  machine  of  the  so-called  U  type  (see  shape  of 
letter  U  suggested  by  Fig.  10)  capable  of  delivering  a  current 
of  80  amperes  at  a  pressure  of  200  volts.  We  will  predeter- 
mine the  speed— let  it  be  600  revolutions  per  minute,  or  10 
per  second.  Further,  suppose  it  is  desirable  that  a  solid  core 

armature generally  known  as  a  Siemens  or  drum  armature — 

shall  be  used,  and  that  the  core  shall  be  a  cylinder  10  inches 
in  diameter  and  10  inches  long.  The  area  inclosed  by  one 
loop  would  then  be  100  square  inches.  It  has  been  experi- 
mentally determined  that  when  soft  iron  has  been  magnetized 
so  highly  that  120,000  of  the  "lines  of  force,"  above  men- 
tioned, may  be  said  to  pass  through  each  square  inch  of 
metal  riormal  to  the  axis  of  the  magnet,  then  the  mass  has 
practically  reached  the  point  of  saturation.  To  carry  the 
iron  to  that  point  requires  a  very  great  M.  M.  F.  Let  us  be 
content  to  obtain  in  the  armature  core  80,000  lines  per  square 
inch.  We  cannot  in  practice  avail  ourselves  of  the  entire 
cross-section  of  the  armature  core  as  an  iron  conductor  of  mag- 
netic lines  of  force,  because  this  core  is  not  made  solid,  but 
generally  is  built  up  of  a  great  number  of  very  thin  plates  of 
iron  separated  by  paper  or  other  non-magnetic  material. 
This  is  done  to  prevent  the  flow  of  currents  of  electricity  in- 
duced by  moving  such  a  conducting  mass  in  a  field  of  force, 


GENERAL  ELECTRICAL  THEORY.  19 

and  which,  in  a  solid  iron  core,  necessarily  of  very  low  resist- 
ance, would  be  very  great.  Their  injurious  effects  would  be 
(i)  heating  of  the  armature  and  (2)  consequent  loss  of  energy. 

The  use  of  paper  reduces  the  iron  to  a  cross-section  about 
85  to  90  per  cent,  that  of  the  area  of  the  loop.  Hence  if  we 
obtain  80,000  lines  per  square  inch  through  the  armature  as 
a  whole,  we  must  obtain  about  18  per  cent,  more  through  the 
iron  of  the  armature,  or  about  95,000  lines  per  square  inch 
of  iron. 

Experience  has  shown  that  if  the  total  lines  of  force  pass- 
ing through  a  section  at  D  T  (Fig.  12)  be  represented  by  100, 


FIG.  12.— MAGNETIC  CIRCUIT  OF  DYNAMO. 

then  the  number  passing  through  the  armature  will  be  from 
60  to  80,  the  remaining  40  to  20  passing  through  the  air,  as 
indicated  in  the  figure. 

With  reasonable  attention  to  shaping  our  machine  we  may 
count  upon  a  loss  not  greater  than  30  per  cent.  In  order, 
then,  to  have  80,000  lines  per  square  inch  through  the  arma- 
ture loops,  we  must  either  have  the  section  at  D  T  of  greater 
area  than  at  V  W,  or  must  force  about  120,000  lines  per  square 
inch  through  the  iron  of  the  magnets,  and  their  connecting 
piece,  the  "  keeper."  Supposing  the  case  not  to  be  one  which 
requires  the  weight  of  iron  to  be  a  minimum,  we  would  pre- 
fer to  increase  the  area  so  that  the  total  lines  at  D  T  shall  be 
distributed  at  the  rate  of  80,000  per  square  inch.  The  sec- 


20  THE   ELECTRIC    RAILWAY. 

tion  A  B  of  the  magnet  core  may  be  nearly  a  mean  between 
the  sections  V  W  and  D  T,  the  lines  per  square  inch  being 
still  80,000. 

To  obtain  absolute  values  for  these  areas  we  may  proceed 
as  follows:  It  has  been  experimentally  shown  that  if  one 
loop  be  rotated  once  per  second  in  a  field  such  that  one  unit 
line  of  force  passes  through  the  loop,  then  the  E.  M.  F.  gen- 
erated in  such  a  loop  will  be  0.00000002  volt.  As  we  have 
chosen  a  speed  of  600  revolutions  per  minute,  or  ten  per  sec- 
ond, we  may  at  once  use  the  larger  coefficient  0.0000002  (see 
page  17).  There  must  be  such  a  number  of  loops  and  such 
an  enclosed  area  through  which  80,000  lines  per  square  inch 
are  passing  that  the  number  of  loops,  multiplied  by  the  total 
lines  of  force  enclosed,  multiplied  by  the  coefficient  0.0000002, 
shall  produce  the  desired  number  of  volts.  It  has  already 
been  assumed  that  the  machine  shall  show  a  difference  of 
potential  of  200  volts  between  tJie  brushes.  It  must  generate 
a  somewhat  greater  E.  M.  F.  since  the  loops  themselves  will 
offer  a  certain  resistance,  requiring  a  certain  E.  M.  F.  to  force 
the  current  over  them. 

Let  us  assume  that  this  requirement  shall  not  exceed  4.0 
volts.  The  total  to  be  generated  will  then  be  204.  Let  us 
represent  by  x  the  area,  in  square  inches,  inclosed  by  the 
armature  loops;  by  y  the  number  of  such  loops;  we  may 
then  write  this  simple  equation 

204  —  x  X  y  X  00000002  x  80000; 

or  204  =  x  X  y  X  0.016; 

204          _  12750 

:  y  x  0.016  ~  ~~y~ 

We  may  readily  obtain  a  working  value  for  y  based  on 
these  considerations.  All  the  loops  represented  by  y  must 
be  connected  by  the  commutator  bars,  either  by  making  only 
one  loop  out  of  each  length  of  wire,  and  connecting  its  ends 
with  adjacent  bars ;  or  by  making  several  loops  from  one 
length  of  wire,  the  number  of  commutatator  bars  being  less- 
ened to  one-half,  one-third,  one-fourth,  etc.  Electrical  con- 
siderations preponderate  in  favor  of  equal  numbers  of  loops 
and  bars,  and  in  larger  machines,  of  comparatively  low  voltage 


GENERAL  ELECTRICAL  THEORY.  21 

and  high  speed,  it  is  good  practice  to  produce  such  equality. 
The  difference  of  potential  between  successive  bars  is  thus 
reduced  to  a  minimum  for  the  given  number  of  loops ;  this 
reduces  the  tendency  to  spark  at  the  brushes;  injurious  in- 
ductive disturbances  in  the  loops  themselves  are  likewise 
reduced  by  decreasing  the  number  of  loops  per  section.  Or- 
dinarily, however,  it  is  difficult,  with  present  methods  of 
commutator  construction,  to  produce  this  equality.  Practice 
has  shown  that  we  should  limit  the  difference  of  potential 
between  successive  bars  to  about  ten  volts.  As  we  have 
in  the  present  case  204  volts,  we  might  have  about  20  bars 
in  each  half  of  the  commutator,  or  40  in  all.  But,  as  we  also 
know  from  practice,  a  considerably  larger  number  of  bars 
may  be  made  into  a  commutator  suitable  for  a  machine  of  the 
kind,  in  view  of  which  we  may  adopt  a  larger  factor  of  safety 
as  to  sparking.  For  convenience  let  us  assume  64  bars  in  the 
commutator.  If  we  further  assume  two  loops  to  the  bar, 
the  value  of  y  becomes  128,  and  the  value  of  x  practically  100 
square  inches.  If  the  cylinder  of  which  this  figure  gives  the 
area  of  cross-section  be  taken  as  ten  inches  long  by  ten 
inches  in  diameter,  we  have  an  armature  of  convenient  and 
usual  size  for  the  conditions  to  be  met.  We  may  now  readily 
determine,  from  what  has  before  been  said,  that  the  section 
D  T  should  be  about  160  square  inches;  the  section  A  B 
about  130  square  inches.  If  these  areas  be  circular,  the 
"diameters  are  about  1 3  inches. 

We  have  now  determined  the  cross-section  of  the  iron  in 
the  magnetic  circuit,  except  that  of  the  pole  pieces.  While 
passing  through  these  the  magnetic  lines  curve  in  toward 
the  armature,  and  those  on  the  upper  side  of  the  shaft  have 
a  path  somewhat  shorter  than  those  below.  To  produce  a 
symmetrical  distribution  through  the  armature  core,  it  is 
desirable  to  make  the  lower  portion  of  the  pole  pieces  quite 
full,  i.e.,  of  as  large  area  asx practicable.  No  exact  rule  need 
here  be  given  for  this  shaping  of  the  pole  pieces,  but,  as  just 
indicated,  the  magnetic  resistance  along  E  F  should  be  as 
nearly  as  possible  equal  to  that  along  E  G.  One  other  con- 
sideration affects  the  shape  of  the  pole  piece  and  its  area 


22  THE    ELECTRIC    RAILWAY. 

normal  to  the  lines  of  force,  that  is,  the  angle  between  the 
lips,  SCR.  Without  entering  into  the  rather  lengthy  discus- 
sion's which  have  been  heard  as  to  the  best  angle,  we  may 
assume  for  an  ordinary  case,  without  serious  error,  that  each 
pole  piece  covers  145°  in  arc  of  the  armature.  The  length  of 
this  arc  on  the  edge  of  the  pole  pieces  will  then  be  very  nearly 
13  inches. 

The  length  of  the  line  E  H,  which  may  be  taken  as  the 
length  of  the  magnetic  circuit  through  the  pole  piece,  de- 
pends on  the  distance  between  the  axes  C  D  and  E  K.  This 
in  turn  depends  on  the  diameter  A  B  (13  inches)  and  the 
breadth  B  L  of  the  space  left  for  the  magnet  coils  and  the  free 
space  required  for  hand  room  and  ventilation.  From  general 
experience  we  may  safely  make  B  L  =  4  inches,  thus  making 
K  D  =  10.5  inches,  the  resulting  length  of  keeper  M  N  thus 
being  about  34  inches  and  E  H  about  7  inches. 

If  we  make  proper  allowance  for  the  air  space  from  surface 
of  pole  to  surface  of  armature  core  (this  will  be  done  later) 
we  may,  as  to  length  of  iron  circuit,  consider  E  H  and  H  C 
as  continuous,  making  a  total  of  12  inches  as  to  length,  and 
without  great  error  we  may  consider  the  area  for  this  length 
as  100  square  inches  (it  is  greater  in  pole,  less  in  armature). 
In  the  keeper  we  have  already  a  denned  length  of  34  inches, 
or  for  one-half  the  magnetic  path  in  this  part  about  17  inches, 
with  cross-section  of  150  square  inches.  If  now  the  length 
E  K  of  the  magnet  and  the  length  of  the  air  gap  were  known, 
the  total  resistance  of  the  magnetic  circuit  would  become 
known.  As  E  K  is  dependent  upon  the  M.  M.  F.  required 
(and  hence  the  space  needed  for  winding  the  magnet  coils), 
and  as  the  M.  M.  F.  is  largely  dependent  on  the  resistance 
of  the  air  gap,  let  us  first  consider  that.  Its  length  from 
iron  to  iron  is  determined  by  the  space  needed  for  laying  the 
loops  of  armature  conductors  (of  copper),  insulation  for  same, 
and  a  reasonable  clearance  between  exterior  of  armature  and 
pole  piece.  This  clearance  we  may  fix  at  o.  i  of  an  inch. 
We  may  also  allow  o.  i  of  an  inch  for  laying  the  armature 
conductors;  or,  since  copper  is  practically  of  equal  magnetic 
stance  with  air,  we  may  say  that  the  air  space  is  0.2  inch 
m  length.  Its  area  is  about  130  inches,  namely  R  S  (=  13 


GENERAL  ELECTRICAL  THEORY.  23 

inches)  X  length  of  pole  piece  (=  10  inches  =  length  of  arma- 
ture).* 

The  total  "  induction"  or  flow  of  magnetic  lines  of  force, 
through  the  armature  is  80,000  X  100  =  8,000,000.  This 
number  must  be  forced  across  the  air  gap,  being  equivalent 
to  about  62,000  per  square  inch.  The  magnetic  resistance 
of  this  air  gap  will  increase  with  its  length  and  decrease  with 
its  cross-section :  we  may  therefore,  simply  for  convenience, 
calculate  the  M.  M.  F.  needed  for  forcing  62,000  lines  across 
one  square  inch;  that  force  will  be  the  same  required  for 
total  flow  across  the  total  section.  From  experience  it  is 
known  that  to  force  one  unit  line  through  an  air  path  one 
inch  long  and  one  square  inch  in  cross-section  we  must  apply, 
as  M.  M.  F.,  0.25  ampere  turn.  In  our  particular  case  the 
length  of  path  is  only  0.2  inch,  while  the  number  of  unit 
lines  is  62,000 — hence  for  the  total  M.  M.  F.  we  have  3,100 
ampere  turns  (0.25  X  62,000  X  0.2  inch  =  3,100). 

Going  to  the  pole  piece  and  armature,  as  has  been  said, 
the  magnetic  resistance  of  iron  varies  with  the  "  induction" 
maintained.  In  this  case  we  require  80,000  lines  per  square 
inch,  and  at  that  density  the  resistance  of  air  is  about  1,200 
times  greater  than  that  of  soft  iron,  or  for  one  unit  line 
through  a  path  one  inch  long  and  one  square  inch  in  cross- 
section  0.000208  ampere  turn  is  required.  Hence  for  total 
length  (12  inches)  and  total  induction  the  ampere  turns  = 
0.000208  X  80,000  x  12  =  200. 

We  may  now  go  to  the  keeper. 

The  machine  being  symmetrical,  we  may  take  half  its 
length  separately,  since  we  are  now  determining  the  M.  M. 
F.  needed  to  overcome  resistances  in  one-half  the  machine, 
and  this  force  is  to  be  supplied  by  the  current  encircling  one 
of  the  magnets.  The  induction  being  80,000  lines  per  square 
inch,  we  have  0.000208  X  80,000  X  M  T  =  about  300. 

Let  us  now  assume  an  approximate  M.  M.  F.  for  the  mag- 
net core.  We  may  use  900  ampere  turns  as  an  outside  figure 

*  If  the  armature  conductors  be  wound  in  slots,  cut  in  the  periphery  of  the  armature 
core,  instead  of  being  laid  on  the  surface  of  this  core,  the  length  of  the  air  gap  proper 
may  be  considerably  diminished.  It  is  then  to  be  remembered  that  since  the  iron  of  the 
core  has,  to  the  depth  of  the  slot,  been  largely  cut  away,  and  the  spaces  filled  with  non- 
magnetic substances,  the  magnetic  resistance  of  this  outer  ring  of  the  core  is  greater  than 
before  the  slotting. 


^4  THE   ELECTRIC   RAILWAY. 

allowing  a  considerable  margin  for  joints  in  the  magnetic 
circuit  Add  this  to  the  other  figures,  we  have  3, 100  +  200  + 
,00  +  000  =  4,500.  Now  this  number  of  ampere  turns  as 
has  been  explained,  may  be  made  up  of  any  two  selected  fac- 
tors representing  current  and  tarns  respectively. 

If  we  wish  to  design  a  series  motor,  the  current  is  at  once 
determined  by  the  original  assumption  to  be  80  amperes. 

In  this  case  the  resistance  and  number  of  turns  would  be 
small.  If  a  shunt  motor  is  under  consideration,  we  should 
make  the  current  quite  small,  that  the  constant  loss  of  power 
in  the  field  may  be  small,  the  resistance  and  number  of  turns 
being  relatively  large.  Assume  1.5  ampere  for  the  field 
current  in  this  case. 

Then  the  number  of  turns  =  4,500 -=-  1.5  =  3>°°°-  The 
resistance  of  these  turns  follows  from  the  fact  that  this  cur- 
rent is  to  be  produced  by  an  electromotive  force  of  100  volts, 
being  one-half  the  total  of  the  normal  E.  M.  F.  for  which 
the  machine  is  calculated.  From  the  rule  previously  given, 
namely, 

C  =    S»    we  have  1.5  =  ^'      .'.  R  =  66  ohms. 
K.  K 

This  then  must  be  the  resistance  of  the  3,000  turns  of  wire. 
The  average  length  of  each  turn,  assuming  the  winding  to 
be  two  inches  deep,  will  be  equal  to  the  circumference  of  a 
circle  about  13.5  inches  diameter — the  magnet-  core  being 
supposed  to  be  of  circular  cross-section.  This  length  equals 
42  inches,  or  for  the  3,000  turns  10,500  feet.  Its  resistance 
per  foot  must  be  66  -=-  10,500  =  0.00629  ohm.  From  tables 
prepared  for  the  purpose  we  find  that  a  wire  having  a  diam- 
eter of  0.052  inch  will  serve  our  purpose.  When  covered 
with  the  usual  cotton  insulation  such  a  wire  would  have  an 
outside  diameter  of  about  .075  inch. 

Approximately  300  such  wires  could  be  laid  along  one  inch 
of  the  length  of  the  magnet,  the  depth  being  two  inches. 
The  length  of  magnet  core  would  then  be  10  inches,  in  order 
to  place  the  3,000  turns. 

Making  now  calculations  for  the  M.  M.  F.  as  determined 
by  this  length  of  magnet  core  we  have :  ampere  turns  re- 
quired =  .  000208  X  80,000  X  10  =  166. 


GENERAL  ELECTRICAL  THEORY.  25 

Our  assumed  value,  namely  900,  is  thus  found  to  be  ample, 
providing  a  large  allowance  for  joints  in  the  magnetic  circuit, 
the  resistance  of  a  good  joint  having  been  estimated  to  be 
equal  to  that  of  8  inches  of  iron  having  a  cross-section  equal 
to  the  area  of  the  joint. 

.  It  remains  now  to  determine  the  size  and  number  of  wires 
to  be  wound  on  the  armature,  and  also  the  number  of  sepa- 
rate sections  into  which  the  total  number  shall  be  divided. 

As  will  be  seen  by  reference  to  Fig.  13,  the  current  in  SOW- 


FIG.  13.— DIAGRAM  OF  ARMATURE  CONNECTIONS. 

ing  over  the  armature  as  a  whole  is  divided  into  two  equal 
parts.  In  this  case  we  will  then  have  40  amperes  to  be 
forced  over  a  circuit  made  up  of  one-half  the  whole  length  of 
wire  on  the  armature,  and  we  have  already  designated  4.0 
volts  as  the  E.  M.  F.  for  this  purpose.  The  resistance  of  this 

A 

half  of  the  armature  wire  must  follow, 40  =  — •      .  •.  R  =  o.  i . 

R 

The  total  length  of  a  turn  around  the  armature  (see  dimen- 
sions) will  be  40  inches,  or  with  a  reasonable  allowance  for 
the  length  of  the  end  going  to  commutator,  and  for  over- 
wrapping  at  the  armature  heads,  we  say  44  inches.  For  one- 
half  the  total  length  we  have,  in  feet,  44  X  64  ^12  =  235. 

The  resistance  per  foot  must  be  o.  i  -f-  235  =  0.00043,  given 
by  a  wire  having  a  diameter  of  .  144  inch  (No.  7  B.  &  S.). 

We  may  use  this,  or  more  conveniently  perhaps  two  smaller 
wires  in  multiple,  and  on  investigation  we  find  that  two  wires 


26  THE    ELECTRIC    RAILWAY. 

of  No.  10  B.  &  S.  gauge  will  give  equal  resistance,  while  per- 
mitting more  space,  measured  along  a  radius  of  the  armature, 
for  insulation  and  clearance. 

All  the  principal  features  in  the  design  have  now  been 
determined.  The  values  assumed  for  speed,  E.  M.  F.,  num- 
ber of  commutator  bars,  etc.,  entering  as  "known  quantities" 
in  the  problem,  have  of  course  been  made  to  "  fit"  more 
accurately  than  is  often  the  case  on  first  trial,  in  the  practice 
of  design.  Certain  refinements  have  not  been  mentioned, 
being  considered  beyond  the  scope  of  this  work. 

Much  might  be  said  concerning  the  effect  of  the  magneti- 
zation of  the  armature  itself  upon  the  poles ;  of  the  mutual 
and  self-induction  of  the  armature  conductors ;  of  the  exact 
shaping  of  the  lips  of  the  pole  pieces;  of  the  important 
phenomena  of  hysteresis,  involving  losses  of  imparted  energy 
due  to  rapid  changes  of  magnetic  polarity  in  the  armature 
core  (or  field  magnets  if  they  be  rotated) ;  of  the  rise  of  tem- 
perature in  the  various  parts  of  the  machine,  etc. ;  but  it  is 
believed  that  these  should  be  left  to  works  more  technical 
than  the  present. 

We  have  spoken  just  now  of  the  principles  controlling  the 
design  of  a  dynamo — that  is,  a  machine  whose  function  is  to 
generate  electric  current  which  may  be  used  for  lighting, 
heating,  or  for  producing  motion  in  other  electric  machines, 
similar  in  construction  to  the  dynamo,  but  whose  function  it 
is  to  transform  the  electric  energy  received  from  the  dynamo 
into  mechanical  energy.  Such  a  secondary  machine  is  called 
generally  a  motor.  The  principles  of  design  are  identical, 
and  indeed  a  machine  made  for  use  as  a  dynamo  may  instead 
serve  as  a  motor  and  vice  versa. 

In  the  dynamo  the  action  may  be  briefly  described  thus : 
Given  lines  of  magnetic  force  and  looped  conductors  located 
in  the  resulting  field  of  force,  a  rotation  of  such  conductors 
produces  electric  currents  and  requires  continuously  supplied 
mechanical  energy  to  continue  such  rotation  against  the 
attraction  set  up  between  the  lines  of  force  and  the  electric 
current  in  the  conductors.  In  the  motor  a  complementary 
action  takes  place  and  maybe  thus  described:  Given  lines 
of  force  and  looped  conductors  located  in  the  resulting  "  field, " 


GENERAL  ELECTRICAL  THEORY.  2/ 

a  flow  of  current  through  such  conductors  will  produce  an 
effort  at  rotation  due  to  attraction  set  up  between  the  electric 
current  and  the  lines  of  force,  and  requires  continuously  elec- 
tric energy  to  produce  rotation  against  the  mechanical  resis- 
tance presented  by  the  friction  of  parts  and  the  useful  work 
or  "load,"  and  to  overcome  electrical  resistances  in  the  arma- 
ture and  magnet  circuits. 

The  energy  for  magnetizing  the  field  is  a  very  definite 
quantity  and  may  be  calculated  as  explained  above.  Consid- 
ering the  armature  of  a  motor,  it  is  apparent  that  when  rotat- 
ing under  the  influence  of  a  current  from  an  external  source 
it  likewise  fulfills  in  all  respects  the  conditions  required  for 
action  as  a  dynamo ;  i.e.,  Tor  the  generation  of  an  electromotive 
force  within  its  own  conductors.  Such  an  electromotive  force 
is  indeed  set  up,  as  shown  by  the  fact  that,  save  when  a 
motor  armature  is  held  mechanically  against  all  possibility 
of  rotation,  the  current  flowing  through  is  not  that  which 
would  be  produced  by  the  given  external  E.  M.  F.  acting 
over  the  given  resistance  of  the  armature,  but  is  a  less  cur- 
rent, such  as  would  flow  over  such  a  resistance,  under  the 
influence  of  an  E.  M.  F.  equal  to  the  difference  between  the 
external  E.  M.  F.  and  the  E.  M.  F.  that  would  be  produced 
by  such  a  machine  if  driven  at  the  given  speed  as  a  dynamo. 
This  is  actually  the  E.  M.  F.  generated  by  the  motor,  and  is 
generally  called  counter  E.  M.  F. 

Now  the  total  energy  absorbed  by  the  motor  is,  of  course, 
that  measured  by  the  product  of  the  external  E.  M.  F.  (called 
usually  the  "impressed"  or  "applied"  E.  M.  F.)  and  the  cur- 
rent that  may  actually  flow ;  or,  to  use  expressions  more 
familiar  in  hydraulics  and  pneumatics,  these  two  elements 
of  pressure  and  of  quantity  when  multiplied  together  meas- 
ure the  power  or  "work." 

The  mechanical  energy  developed  by  the  motor  armature 
is  measured  by  the  product  of  the  current  in  the  armature  and 
the  counter  E.  M.  F.  The  ratio  between  the  electrical  energy 
absorbed  and  the  mechanical  energy  given  out  by  the  motor 
is  the  measure  of  its  efficiency.  We  may  express  absorbed 
energy  by  C  X  E,  and  developed  energy  by  C  X  E'  (E  and  E' 
being  impressed  and  counter  E.  M.  F.  respectively).  The 


28  THE   ELECTRIC    RAILWAY. 

C*  \/  Tn^'  TH*' 

efficiency   then   becomes  ^      ^    =  g  •        This  efficiency  is 

found  in  many  motors  to  be  as  high  as  93  to  95  per  cent., 
leaving  little  to  be  desired.  The  same  machine  may  be 
caused,  by  overload,  to  work  at  lower  efficiencies,  since  the 
great  currents  required  for  the  work  require  greater  propor- 
tions of  the  absorbed  energy  simply  to  force  these  currents 
over  the  internal  resistance  of  the  motor,  leaving  less  for 
external  useful  work.  This  point  will  be  more  fully  devel- 
oped later. 


CHAPTER    II. 

CONCERNING   PRIME    MOVERS. 

BY  prime  movers  we  mean  such  mechanisms  as  are  fitted  to 
utilize  somewhat  directly  natural  sources  of  energy  for  the 
production  of  mechanical  power.  So  far  as  electrical  pur- 
poses are  concerned,  the  number  of  available  prime  movers 
is  very  limited,  and  when  we  take  into  consideration  the  par- 
ticular demands  to  be  met  in  the  supply  of  electrical  power 
for  traction  purposes,  we  find  the  only  generally  available 
prime  movers  to  be  steam  engines  and  water-wheels.  One  or 
two  very  small  electric  roads  in  England  are  operated  by 
gas  engines,  but  in  this  respect  they  are  quite  alone,  and  the 
practice,  for  various  reasons,  is  seldom  to  be  advised.  It 
does  not  befit  our  purpose  here  to  enter  into  any  exhaustive 
discussion  of  the  theory  of  the  steam  engine,  or  to  describe 
in  detail  the  very  numerous  modifications  of  the  few  types 
that  are  met  in  modern  engineering  practice.  We  shall 
merely  attempt  to  give  in  a  very  brief  form,  without  having 
recourse  to  mathematics,  the  general  principles  involved  in 
the  construction  and  operation  of  modern  engines,  and  to 
give  some  account  of  the  means  by  which  their  action  and 
particular  properties  may  be  most  conveniently  investigated. 
Having  done  this,  it  will  only  remain  to  describe  in  a  manner 
necessarily  condensed  the  general  principles  of  the  utiliza- 
tion of  water  power.  . 

The  steam  engine  is  to-day  our  most  universal  means  of 
obtaining  mechanical  power,  and  although  the  theory  of  its 
action  is  somewhat  complicated  the  main  facts  are  easily 
understood.  The  fundamental  principle  of  heat  engines,  of 
which  steam  engines  are  the  most  familiar  variety,  is  the 
production  of  pressure  in  a  gas  by  the  transference  of  heat 
energy  to  it,  and  the  utilization  of  this  pressure  to  recover, 
in  the  form  of  mechanical  motion,  the  energy  thus  given.  The 

29 


,0  THE   ELECTRIC   RAILWAY. 

primary  source  of  energy  is  that  which  exists  as  potential 
chemical  energy  in  fuel  of  various  sorts.  The  gas  almost 
universally  employed  is  the  vapor  of  water;  in  other  words, 
steam.  It  is  a  singular  fact  in  physics  that  all  gaseous  bodies 
are  remarkably  alike  in  their  dynamical  properties.  They 
expand  and  contract,  if  free  to  do  so,  in  almost  exactly  the 
same  amount  when  the  temperature  varies ;  or,  if  the  volume 
be  kept  constant,  the  pressure  varies  with  the  temperature 
very  uniformly  for  all  gases  and  all  temperatures. 

If,  then,  we  are  to  utilize  steam  pressure  practically  in  an 
engine  cylinder,  the  higher  the  temperature  of  the  steam  the 
greater  will  be  its  pressure.  The  amount  of  work  that  can  be 
gotten  out  of  a  given  quantity  of  steam  at  a  certain  pressure 
obviously  depends  on  the  extent  to  which  we  are  able  to 
utilize  that  pressure.  If  we  could  employ  it  all  in  pushing- 
on  a  piston  we  should  be  able  to  get  very  efficient  engines 
indeed ;  but  since  we  are  living  in  an  atmosphere  that  has 
a  pressure,  and  in  a  world  that  has  sometimes  a  rather  high 
temperature,  we  are  in  practice  totally  unable  to  avail  our- 
selves of  all  the  pressure  produced.  In  other  words,  if  we 
give  a  certain  amount  of  heat  to  a  volume  of  steam,  creating 
thereby  a  high  pressure  and  temperature,  we  shall  be  unable 
to  get  all  the  heat  energy  back  in  the  form  of  mechanical  mo- 
tion of  the  engine  simply  because  of  the  necessary  limitations 
imposed  by  our  conditions  with  respect  to  pressure  and  tem- 
perature. Aside  from  these  the  energy  lost  is  small  in 
amount. 

It  is  found  by  experiment  that  if  we  were  to  have  a  unit 
volume  of  some  gas,  like  air,  at  the  temperature  of  melting  ice, 
one  degree  Fahrenheit  rise  of  temperature  would  increase  its 
pressure  by  i-493d  part.  Consequently,  there  might  be  some 
temperature  so  low  that  if  it  were  possible  to  reach  it  the  gas 
would  have  no  pressure ;  in  other  words,  it  would  have  lost 
its  elasticity  and  given  up  all  its  energy.  This  point  is  461 
degrees  below  zero  Fahrenheit,  as  appears  from  the  rate  of 
increase  just  given.  This  particular  temperature  is  known 
as  the  absolute  zero.  If  we  were  able  to  start  at  this  point, 
and  by  applying  heat  to  raise  the  temperature  of  any  gas  up 
to  our  present  working  temperature,  we  should  give  to  that 


CONCERNING   PRIME    MOVERS.  31 

gas  a  certain  amount  of  heat  energy,  all  of  which  could  be 
recovered  if  we  were  able  to  let  it  expand  and  cool  itself  off 
by  expending  its  heat  as  mechanical  work  until  all  its  press- 
ure was  exhausted,  when  its  temperature  would  be  back  to 
the  starting  point  of  minus  461  degrees.  Unfortunately,  we 
are  unable  either  to  start  with  a  gas  or  vapor  at  such  a  low 
temperature,  or  to  reduce  its  pressure  after  heating  any- 
where nearly  to  zero. 

Obviously  we  cannot  use  all  its  pressure  unless  we  get 
down  to  the  absolute  zero,  and  in  practice  we  are  compelled 
to  cease  utilizing  its  expansive  power  when  the  temperature 
goes  down  to  the  every-day  temperature  at  which  we  live ;  so 
only  part  of  the  whole  amount  of  heat  can  be  recovered  as 
mechanical  work,  the  exact  proportion  depending  on  the  ex- 
tent to  which  we  are  able  to  cool  by  expansion  the  working 
gas,  allowing  it  to  do  work  and  lose  pressure.  If,  for  example, 
we  work  with  gas  at  400  degrees  Fahrenheit,  and  let  it 
expand  until  it  cools  down  to  zero  Fahrenheit,  we  shall  utilize 
that  portion  of  the  pressure  of  the  gas  that  corresponds  to  a 
change  in  temperature  of  400°.  All  the  pressure  which  cor- 
responds to  the  temperature  from  zero  down  to  the  point 
where  pressure  ceases  is  unavailable.* 

The  efficiency  of  such  a  transformation  of  energy  is,  then, 
somewhat  less  than  50  per  cent.  To  be  exact,  the  effi- 

'p  'p 

ciency  of  the  heat  engine  is  equal  to  the  fraction      '  „ — — , 

where  T,  is  the  highest  temperature  to  which  the  gas  or 
vapor  has  been  heated,  and  TQ  the  temperature  at  which  we 
are  compelled  to  stop  utilizing  its  pressure,  T  being  always 
reckoned  from  the  absolute  zero.  In  practical  engineering, 
T2  is  the  temperature  of  exhaust  or  condensation.  The 
general  law  of  the  efficiency  of  the  utilization  of  heat  by  en- 


*  In  ordinary  engines  a  nearly  saturated  vapor,  such  as  steam,  is  used,  and  in  produc- 
ing it  much  heat  is  taken  to  drive  the  substance  from  the  liquid  to  the  gaseous  state,  so 
that,  although  we  begin  to  give  heat  to  the  gas  at  a  comparatively  high  temperature,  the 
total  heat  required  is  much  as  if  we  had  started  at  or  near  the  absolute  zero.  As  various 
liquids  require  different  amounts  of  heat  to  vaporize  them,  one  mi^ht  think  that  there 
could  be  a  great  gain  by  properly  choosing  the  liquid  In  fact,  however,  the  liquids 
that  vaporize  with  little  heat  per  unit  weight  give  a  considerably  smaller  total  volume 
of  vapor,  so  that,  so  far  as  working  in  engines  ib  concerned,  the  particular  liquid  used 
makes  little  or  no  difference. 


32  THE   ELECTRIC    RAILWAY. 

giiies  is  that  the  heat  transformed  into  mechanical  energy 
is  to  the  whole  heat  received  by  the  working  fluid  as  the 
range  of  temperature  is  to  the  absolute  temperature  reached  by 
the  fluid.  The  perfect  efficiency  theoretically  possible  can 
never  be  reached  because  of  our  inability  to  command  suffi- 
cient range  of  temperature,  but  the  best  modern  engines 
come  quite  near  to  the  maximum  efficiency  possible  between 
the  temperature  limits  attainable  in  practice.  Taking  nature  as 
we  find  it,  and  even  condensing  our  working  gas  at  ordinary 
temperatures,  we  can  really  recover  as  mechanical  work  a 
very  respectable  proportion  of  heat.  Sufficient  has  been  said, 
however,  to  show  that  the  higher  the  initial  pressure  given  to 
the  steam  and  the  lower  the  pressure  at  which  it  is  exhausted 
or  condensed,  the  more  efficient  will  be  the  engine  in  con- 
verting the  heat  energy  of  coal  into  mechanical  power. 

Now  in  every-day  work  the  pressure  of  steam  is  utilized  in 
only  one  way,  that  is,  by  employing  it  to  drive  a  piston  along 
a  steam  cylinder,  thereby  working  a  driving  wheel  of  some 
kind  by  means  of  the  piston  rod.  The  rudimentary  steam 
engine,  then,  consists  of  a  closed  cylinder  containing  a  mov- 
able piston,  with  a  piston  rod  reaching  into  the  outside  air. 
The  pressure  of  the  steam,  admitted  to  the  cylinder  by  valves, 
drives  the  piston  to  and  fro.  In  some  of  the  earliest  engines 
the  steam  was  admitted  to  the  cylinder  through  a  valve  oper- 
ated by  hand,  and  when  the  end  of  the  stroke  wTas  reached 
the  steam,  instead  of  being  allowed  to  escape,  was  condensed 
by  a  spray  of  water  thrown  inside  the  cylinder;  afterward 
the  steam  was  allowed  to  escape  at  the  end  of  the  stroke 
through  an  exhaust  valve,  or  else  to  flow  into  a  separate 
chamber,  where  it  was  condensed.  Finally,  about  one  hun- 
dred years  ago,  the  engine  was  provided  with  valves  to  admit 
automatically  the  steam  to  the  cylinder,  and  to  let  it  escape  at 
the  end  of  the  stroke.  With  various  modifications,  that  is 
the  form  of  machine  used  to-day. 

Fig.  14  shows  a  diagram  of  the  working  parts  of  a  modern 

engine  very  extensively  used  for  electric  light  and  power  pur- 
Its  cylinder  is  provided  with  a  steam  port  A,  at  each 

tid,  communicating  with  the  steam  chest  S  S.  This  latter  is 
placed  immediately  next  the  cylinder,  and  receives  the  steam 


CONCERNING   PRIME    MOVERS. 


33 


at  full  boiler  pressure  through  the  supply  pipe.  The  entrance 
of  the  steam  into  the  cylinder  is  controlled  by  the  valve  V, 
which  is  a  hollow  cylinder  closed  at  the  ends  and  contracted 
somewhat  in  the  middle.  This  piston  valve  has  a  slight  to- 
and-fro  motion  communicated  to  it  by  an  eccentric  on  the  en- 
gine shaft,  and  slides  backward  and  forward  nra  cylindrical 
cavity  in  the  steam  chest ;  at  each  end  of  this  is  an  exhaust 
pipe  communicating  with  the  outer  air,  or  with  the  condenser. 
Observe  that  in  this  arrangement  the*  valve  is  surrounded 
on  all  sides  by  live  steam,  and  consequently  is  not  pressed 
against  any  of  the  wearing  surfaces:  in  other  words,  it  is 
.what  is  called  a  balanced  valve.  In  the  position  shown  the 
valve  is  just  admitting  steam  to  the  piston  end  of  the  cylin- 
der; a  very  even  flow  is  secured,  not  only  around  the  shoul- 
der of  the  valve  as  its  enlarged  portion  passes  beyond  the 

fin        rm        rrn 


FIG.  14.— WORKING  PARTS  OF  SIMPLE  ENGINE. 

steam  port,  but  also  through  the  ports  P  P  at  the  opposite  end 
of  the  valve  and  through  the  inner  space.  At  the  same  time 
it  will  be  seen  that  at  the  other  end  of  the  cylinder  the  valve 
has  moved  in  its  bearing  completely  past  the  steam  port, 
allowing  the  steam  to  flow  out  freely  into  the  exhaust ;  when 
3 


24  THE   ELECTRIC   RAILWAY. 

the  piston  has  moved  a  little  way  on  its  return,  the  port  At 
through  which  the  steam  has  been  flowing,  will  be  closed  as 
the  solid  part  of  the  valve  slides  over  it,  and  open  for  the 
exhaust  at  the  other  end  of  the  stroke  when  the  valve  slides- 
clear  beyond.  It  will  thus  be  seen  that  the  same  mechan- 
ism admits  the  steam  to  the  cylinder  or  allows  it  to  flow  into- 
the  exhaust,  according  to  the  relative  positions  of  the  valve. 
This  rudimentary  description  of  the  steam  engine  will  be- 
unnecessary  to  most*  of  our  readers,  but  will  prove  useful  in. 
connection  with  points  to  be  presently  mentioned  with  refer- 
ence to  the  economical  use  of  steam. 

Suppose,  now,  that  we  have  communicated  heat  to  a  steam. 
boiler  to  produce  a  quantity  of  steam  at  an  ordinary  working- 
pressure — such,  for  example,  as  100  pounds  to  the  square 
inch  in  excess  of  the  ordinary  pressure  of  the  atmosphere — 
a  very  practical  question  arises :  how  can  that  steam  be  so- 
utilized  in  an  engine  as  to  give  the  maximum  return  in. 
mechanical  work?  From  what  we  have  already  seen,  it  will 
be  evident  that  the  steam  must  not  be  allowed  to  cool  off  and 
lose  pressure,  because  all  the  heat  so  lost  is  simply  so  much 
possible  mechanical  work  thrown  away.  Consequently,  ta 
begin  at  the  beginning,  the  pipe  leading  the  steam  from  the 
boiler  to  the  engine  ought  to  be  thoroughly  jacketed,  so  that 
the  steam  will  not  get  cooled  on  its  way  to  the  engine.  Hav- 
ing arrived  at  the  steam  chest,  it  is  evidently  best  to  employ, 
if  possible,  the  full  pressure  of  the  steam  to  push  along  the 
piston;  naturally,  therefore,  the  steam  ports  and  other  aper- 
tures through  which  the  steam  has  to  pass  must  be  large 
enough  to  permit  its  passage  without  serious  check  and 
reduction  of  pressure,  such  as  is  known  as  wire-drawing- 
among  engineers.  And  in  general,  the  efficiency  of  the 
engine  will  be  increased  by  receiving  the  steam  at  the  high- 
est temperature,  that  is,  at  the  highest  pressure  possible,  and 
discharging  it  at  the  lowest  temperature  possible ;  in  other 
words,  after  having  obtained  all  the  heat  available  from  it  in 
the  form  of  mechanical  work. 

The  fundamental  principle  of  the  efficient  working  of 
steam  depends  on  following  out  this  very  obvious  suggestion, 
that  has  been  admirably  stated  by  Rankine  as  follows; 


CONCERNING   PRIME    MOVERS.  35 

41  Between  given  limits  of  temperature  the  efficiency  of  a 
thermo-dynamic  engine  is  the  greatest  possible  when  the 
whole  reception  of  heat  takes  place  at  the  higher,  and  the 
whole  rejection  of  heat  at  the  lower  limit." 

It  is  desirable,  therefore,  in  admitting  steam  to  the  cylin- 
der to  let  it  in,  so  far  as  it  is  admitted  at  all,  at  full  boiler 
pressure,  and  to  exhaust  it  as  completely  as  may  be  at  the 
lowest  available  pressure.  A  vast  amount  of  ingenuity  has 
been  spent  in  arranging  the  steam  engine  so  as  to  produce 
this  result ;  in  other  words,  to  move  the  valves  in  such  a  way 
that  the  steam  admitted  may  come  in  at  a  uniform  high 
pressure  and  be  exhausted  at  a  uniform  low  pressure.  The 
difference  between  a  good  and  a  bad  engine  lies  largely  in  the 
success  with  which  this  has  been  accomplished.  In  the  early 
days  of  the  steam  engine  it  was  usual  to  leave  the  admission 
valve  open,  allowing  the  steam  to  rush  in  direct  from  the 
boiler,  until  the  piston  rod  reached  the  end  of  its  stroke. 
Such  a  plan  permitted  a  given  engine  to  do  a  great  deal  of 
work,  because  the  piston  was  all  the  time  subjected  to  the  full 
pressure  of  the  steam,  but  at  the  same  time  it  is  obviously 
very  uneconomical,  since  the  steam  when  we  are  through 
using  it  will  have  nearly  the  same  temperature  and  pressure 
as  at  first,  the  deficiency,  which  has  gone  into  work  in  push- 
ing the  piston  along,  being  kept  up  by  fresh  supplies  from 
the  boiler  during  the  stroke.  An  engine  of  this  character 
requires,  evidently,  enormous  amounts  of  fuel,  so  one  of 
the  early  improvements  in  engineering  practice  was  to  use 
the  steam  expansively ;  in  other  words,  to  admit  to  the  cylin- 
der a  comparatively  small  amount  of  steam,  and  let  it  finish 
up  the  stroke  of  the  piston  by  its  own  expansion. 

Under  these  circumstances,  steam  enters  at  full  boiler  press- 
ure only,  perhaps,  for  a  quarter  of  a  stroke;  the  supply 
valve  being  then  closed,  the  steam  expands  and  uses  up  its 
heat  quite  completely  in  doing  work  on  the  piston,  so  that 
when  the  stroke  is  completed  the  steam  exhausted  will  be 
low  in  temperature  and  pressure — or,  in  other  words,  work- 
ing steam  expansively  enables  us  to  increase  the  range  of 
temperature  through  which  our  heat  engine  works,  and  hence 
increases  its  efficiency.  In  so  using  steam,  however,  the 


36  THE   ELECTRIC    RAILWAY. 

pressure  produced  on  the  piston  is  not  uniform,  and  should 
we  desire  to  compute  the  rate  at  which  the  engine  is  doing' 
work,  it  is  necessary  to  know  the  average  pressure  that  the 
expanding  steam  has  exerted.  An  instrument  for  finding 
this  average  will  be  described  later. 

If  an  engine  is  allowed  to  condense,  that  is,  to  exhaust  its 
steam  into  a  vessel  that  is  kept  cool,  it  is  possible  still  further 
to  increase  the  working  range  of  pressure  by  very  nearly 
the  pressure  of  the  atmosphere,  and  hence  the  efficiency. 
Wherever  plenty  of  water  for  keeping  the  condenser  cool  is 
available  condensing  engines  are  very  frequently  used,  and 
are  especially  useful  when  the  engine  is  but  lightly  loaded. 
By  so  getting  rid  of  the  steam,  there  is  a  very  perceptible  sav- 
ing. From  what  has  been  said  we  are  prepared  to  pass  at 
once  to  the  practical  discussion  of  every-day  engines. 

Following  Rankine's  general  principle,  we  may  begin  at 
once  by  saying  that  the  ideal  valve  gear  for  an  engine  is  that, 
which  can  open  instantaneously  when  steam  is  wanted, 
admits  it  to  the  cylinder  at  full  boiler  pressure,  and  closes, 
instantly,  to  avoid  letting  any  steam  in  at  a  lower  pressure 
when  it  is  desired  to  shut  off  the  steam  supply.  When  the 
expansion  of  the  steam  is  completed  the  exhaust  valve  should 
open  instantly  and  let  the  pressure  down  to  that  of  the  out- 
side air,  or  the  condenser,  at  once.  From  the  diagram  of  the 
engine  just  given  you  will  see  that  these  conditions  are 
but  partially  fulfilled ;  for  so  long  as  the  same  ports  are  used 
for  admission  and  exhaust,  and  are  controlled  by  a  single 
sliding  valve,  the  engine  is  not  always  capable  of  proper 
adjustment  to  the  conditions  under  which  it  is  working, 

because  the  four  functions  performed  by  the  single  valve 

the  opening  and  closing  of  the  supply  ports  and  the  opening 
and  closing  of  the  exhaust  ports— are  not  independent  of 
each  other,  and,  consequently,  have  to  be  so  related  as  to  pro- 
duce the  best  average  effect,  not  always  the  most  desirable  one 
in  a  particular  case.  It  was  for  the  purpose  of  avoiding  the 
difficulties  met  in  these  single-valve  engines  that  more  com- 
plicated valve  gears  have  been  introduced.  The  best  type 
of  these  is  the  Corliss,  which  has  been  used  for  over  forty 
years. 


CONCERNING   PRIME    MOVERS. 


37 


In  this  form  of  engine,  shown   in  Figs.    15  and   16,  four 
separate  valves  are  employed,  two  to  admit  the  steam  to  the 


FIG.  15.— CORLISS  VALVE  MOTION. 

cylinder  and  two  others  to  let  it  out  when  it  nas  been  used : 
they  operate  by  a  slight  turning  motion  about  their  axes,  and 
are  usually  in  the  form  of  slightly  tapering  cones,  having  the 
steam  ways  cut  as  long  longitudinal  slots.  It  is  apparent  that 
valves  of  this  sort  can  be  thrown  wide  open  very  quickly  and 
closed  as  speedily,  and  that  they  are  capable  of  any  sort  of 
independent  adjustment ;  the  result  is  apparent  in  the  supe- 
rior economy  that  is  obtained  by  such  mechanisms. 

,'579414 


38  THE   ELECTRIC    RAILWAY. 

The  Corliss  valve  gear  has  various  modifications,  but  all 
retain  the  distinguishing  characteristic  of  four  independ- 
ent valves  separately  adjustable.  The  admission  valves  are 
opened  by  an  eccentric,  but  are  closed  by  gravity  or,  in  later 
designs,  by  vacuum  pots.  All  four  valves  are  driven  (as 
shown  in  Fig.  15)  from  a  wrist  plate  pivoted  on  a  pin  project- 
ing from  the  center  of  the  cylinder — this  wrist  plate  is  itself 
actuated  by  the  eccentric  on  the  shaft,  and  has  attached  to  it 
four  links  connecting  it  with  the  four  valves.  The  result  of 
this  method  of  driving  is  that  the  valves  are  opened  very 
promptly,  held  open,  and  closed  rapidly.  The  two  upper 
valves  in  the  figure  are  the  admission  valves,  and  are  closed 
by  the  vertical  rods  seen  attached  to  them,  which  pass  into 
the  vacuum  pots  below  the  floor.  The  links  leading  to  the 


FIG.  i6.-SECTioN  OF  CORLISS  CYLINDER  AND  VALVES. 


steam  valves  are  provided  with  catches.     When  these  are  dis- 
engaged the  valves  are  free  to  close,  and  each  catch  takes 
hold  on  its  backward  stroke  ready  to  open  its  valve.     The 
rods  A  and  B  control  the  position  of  these  catches,  so  that 
the  valve  may  be  released  and  closed  at  any  point  in  the 
rtion  of  the  piston  up  to  nearly  half  the  full  stroke.     These 
rods  are  controlled  by  an  ordinary  centrifugal  governor   usu- 
Uly  belted  to  run  much  faster  than  the  engine  in  order  to 
t  sensitive.     This  Corliss  valve  gear  is  used  only  on 
omparahvely  low-speed  engines,  140  revolutions  per  minute 
less,  because  the  vacuum  pots  or  weights  that- close  the 


CONCERNING    PRIME    MOVERS.  39 

valves  do  not  work  rapidly  enough  to  operate  at  a  much 
higher  speed. 

For  most  engines  running  two  or  three  hundred  revolu- 
tions per  minute  a  simpler  valve  gear,  much  like  that  shown 
in  Fig.  14,  is  almost  universally  employed.  This  may 
take  many  forms,  most  of  them,  however,  retaining  the 
same  general  characteristic  of  a  balanced  valve  simply  and 
strongly  made,  and  controlling  a  pair  of  ports  that  serve  both 
for  admission  and  exhaust.  The  particular  diagram  shown 
refers  to  the  Armington  &  Sims  engine,  which  is  used  to  a 
very  large  extent  in  electric  light  and  power  work.  But 
something  more  than  proper  valve  motion  is  necessary  to 
secure  the  best  results  from  an  engine.  One  of  the  most 
serious  losses  met,  particularly  in  engines  driving  electric 
railway  plants,  is  cylinder  condensation,  or  loss  of  heat  due 
to  the  steam  being  cooled  by  the  metallic  portions  of  the  cyl- 
inder; the  result  is  that  a  certain  amount  of  heat  which  ought 
to  be  utilized  on  the  piston  is  wasted. 

Considerable  loss  of  this  kind  is  almost  certain  to  take 
place  where  an  engine  is  underloaded.  The  steam  is  admitted 
at  a  high  pressure  and  expanded  altogether  too  much,  during 
which  process  a  portion  of  it  gets  condensed.  There  is  for 
every  steam  pressure  a  particular  amount  of  expansion  that 
gives  the  best  results;  if  more  than  this  be  employed,  the 
engine  generally  suffers  from  condensation  and  excessive 
cooling  of  the  steam  by  radiation  of  heat  through  the  sides 
of  the  cylinder ;  while  if  less  expansion  be  used,  the  steam 
is  rejected  while  it  still  has  a  considerable  amount  of  valu- 
able energy  which  is  thus  lost. 

When  high  steam  pressures  are  to  be  used,  as  is  most 
desirable  on  the  score  of  economy,  it  is  best  that  the  expan- 
sion should  not  be  carried  out  in  a  single  cylinder,  but  con- 
secutively in  two  or  more.  Engines  so  arranged  are  called 
compound.  The  advantage  of  /this  arrangement  lies  largely 
in  avoiding  the  losses  incidental  to  changes  of  temperature 
that  take  place  during  expansion ;  the  more  nearly  uniform  the 
temperature  of  the  cylinder  can  be  maintained,  the  less  loss 
from  radiation  and  condensation.  Where  the  temperature 
range  of  steam  in  the  cylinder  is  great,  as  in  the  case  where 


40  THE   ELECTRIC    RAILWAY. 

high  initial  pressures  and  high  expansions  are  used,  it  is  a  diffi- 
cult matter  to  keep  the  cylinder  at  a  steady  enough  temperature 
to  allow  economical  expansion  of  the  steam.  If,  however, 
the  expansion  is  distributed  over  two  or  more  cylinders,  only 
one  of  them  will  communicate  with  the  condenser,  in  itself  a 
ready  source  of  cooling,  and  each  cylinder  can  be  kept  at  a 
temperature  much  more  favorable  to  escaping  loss  than  if  the 
entire  temperature  range  of  expansion  were  in  a  single  cylin- 
der. Engines  in  which  this  useful  plan  is  carried  out  are 
coming  into  very  extensive  use.  The  compound  engine, 
either  non-condensing  or  condensing,  has  found  its  way  into 
a  large  number  of  electric  central  stations,  and  the  triple- 
expansion  engine,  in  which  the  work  of  the  steam  is  still 
further  subdivided,  is  gradually  displacing  the  compound 
engine  where  large  powers  are  required.  The  compound 
construction  is  generally  more  advantageous  in  condensing 
than  in  non-condensing  engines,  and  under  favorable  circum- 
stances will  save  something  like  40  per  cent,  of  the  fuel  that 
would  otherwise  be  required. 

A  very  important  part  of  every  engine  is  the  governor.  In 
its  original  form  it  consisted  simply  of  a  pair  of  balls  sup- 
ported by  arms  hinged  to  a  vertical  shaft  put  in  rotation 
'from  the  main  shaft  of  the  engine ;  links  from  each  ball  led 
to  a  collar  capable  of  vertical  play  up  and  down  the  shaft. 
This  collar  gave  motion  to  a  lever  controlling  the  main  steam 
valve,  and  when,  owing  to  the  high  speed  of  the  engine, 
the  balls  were  thrown  outward  by  centrifugal  force,  the  col- 
lar was  raised  and  the  steam  partially  cut  off.  The  objec- 
tions to  this  form  of  governor  are  numerous ;  two  of  them 
being  lack  of  sensitiveness,  owing  to  the  considerable  amount 
of  work  that  has  to  be  done  by  the  governor  in  operating  a 
steam  valve,  and  the  fact  that  engines  equipped  with  this 
throttling  governor  work  at  a  fixed  cut-off,  that  is,  the  steam 
is  always  admitted  to  the  cylinder  for  a  definite  part  of  the 
stroke,  but  at  a  pressure  depending  on  the  amount  the  steam  is 
wire-drawn  in  passing  the  half -closed  valve.  By  thus  low- 
ering the  initial  pressure  the  efficiency  of  the  engine  is  decid- 
edly diminished.  One  of  the  great  improvements  made  in  the 
introduction  of  the  Corliss  valve  gear  was  a  successful  way  out 


CONCERNING    PRIME    MOVERS.  41 

of  both  of  these  difficulties.  In  the  first  place,  the  work  done 
by  the  governor  is  very  little,  only  sufficient  to  release  the 
catch  on  the  link  that  works  the  admission  valve  and  permit 
the  latter  to  close.  This  gives  such  sensitiveness  that  a 
very  slight  change  of  speed  "vill  suffice  to  move  the  govern- 
ing levers.  The  second  advantage  is  that  instead  of  admit- 
ting steam  to  the  cylinder  for  a  fixed  portion  of  the  stroke, 
but  at  varying  pressure,  the  governing  is  accomplished  by 
changing  the  cut-off.  In  other  words,  when  the  load  grows 
heavy  and  the  engine  begins  to  slow  down,  the  catch  that 
holds  the  admission  valve  is  shifted  so  as  to  keep  the  valve 
open  during  a  greater  portion  of  the  stroke,  thus  furnishing 
a  higher  average  pressure  during  the  stroke.  The  steam  is 
thus  used  at  nearly  the  full  boiler  pressure  and  temperature, 
but  in  amounts  depending  on  the  work  to  be  done. 

Although  the  Corliss  form  of  governor  is  capable  of  very 
excellent  Nwork,  and  is  a  vast  improvement  over  any  of  the 
throttling  governors,  it  still  leaves,  in  its  usual  form,  much  to 
be  desired  as  regards  keeping  the  engine  absolutely  constant 
in  speed. 

We  may  as  well  state  at  once  that  so  far  as  most  elec- 
tric railway  service  is  considered  an  engine  cannot  be 
kept  at  really  constant  speed  by  any  device  yet  invented. 
There  are  good  and  bad  governors,  but  there  is  no  perfect 
governor.  One  of  the  reasons  for  this  is  the  enormous  rapid- 
ity of  the  variations  in  load  encountered  in  driving  railway 
generators  for  a  small  road.  Quadrupling  the  load  will  slow 
down  any  engine  with  any  kind  of  governor.  The  decrease 
in  speed  is,  of  course,  only  temporary,  and  in  a  few  seconds 
the  engine  recovers  itself.  But  even  with  the  most  reliable 
and  sensitive  forms  of  governor  now  constructed  the  moment- 
ary slowing  down  is  quite  noticeable,  although  counted  min- 
ute by  minute  the  speed  may  be  almost  uniform.  In  the 
Corliss  arrangement  for  governing  the  faults  are  two.  First, 
the  speed  of  the  engine  in  revolutions  per  minute  is  so  slow 
that  opportunities  to  govern  are  too  infrequent,  for  the  drop 
cut-off  used  in  Corliss  engines  is  seldom  worked  above  100 
revolutions  per  minute,  and  if  forced  beyond  this  point  it  is 
apt  to  fail  in  promptitude.  Hence  a  very  perceptible  fraction 


42         .  THE   ELECTRIC    RAILWAY. 

of  a  second  elapses  between  the  action  of  the  governor  and  the 
next  ensuing  opportunity  to  shift  the  valve.  Besides  this,  the 
inertia  of  the  governor  itself  causes  some  delay.  The  second 
fault  is  one  that  is  common  to  all  fly-ball  governors  of  the  kind 
described ;  they  act  too  uniformly.  In  other  words,  the  force 
tending  to  pull  the  balls  downward  is  uniform,  and  the  posi- 
tion taken  by  the  balls  for  any  given  speed  of  the  engine  is 
always  the  same,  so  that  there  is  continually  a  fixed  relation 
between  the  action  of  the  governing  balls  and  the  position 
of  the  valves. 

Now,  if  instead  of  pulling  the  balls  down  by  gravity  a 
force  can  be  substituted  for  it  that  will  vary  with  the  change 
in  the  position  of  the  balls,  so  that  the  shifting  of  the  valves 
may  go  on  rapidly  until  the  engine  comes  to  the  required 
speed,  we  shall  have  as  the  result  a  governor  much  more 
sensitive  than  the  ordinary  form,  especially  as  regards 
changes  in  steam  pressure  or  in  load.  On  all  modern  high- 
speed engines  such  a  governor  is  in  use.  Most  of  the  smaller 
engines  nowadays  are  high-speed  machines,  running  from 
two  to  four  hundred  revolutions  per  minute  according  to  size. 
The  governor  is,  in  such  machines,  usually  placed  where  it 
will  act  directly  on  the  eccentric  to  change  the  throw  of  the 
valves.  Fig.  17  shows  a  governor  of  that  class.  Its  opera- 
tion will  be  seen  at  a  glance.  Two  weighted  arms  pivoted 
near  the  periphery  of  the  fly-wheel  are  thrown  outward  by 
centrifugal  force,  and  their  motion  is  resisted  by  a  pair  of 
powerful  spiral  springs,  acting  in  this  case  in  tension ;  the 
motion  of  these  arms  is  transmitted  through  a  pair  of  levers, 
clearly  shown  in  the  cut,  to  lugs  on  the  eccentric,  and  tend 
to  shift  the  latter's  position  on  the  shaft,  and  thus  vary  the 
valve  motion.  The  engine  can  be  conveniently  adjusted  for 
various  speeds  by  varying  the  tension  of  the  springs  and  the 
position  of  the  weights  on  the  arms,  or  both.  These  govern- 
ors are  much  wider  in  range  of  action  and  far  prompter  in 
motion  than  the  fly-ball  governors  previously  described. 

vSome  of  them  permit  the  admission  of  steam  for  over  four- 
fifths  of  the  entire  stroke,  thus  taking  care  of  an  overload 
very  effectively.  We  thus  see  that  there  are  two  quite  dis- 
tinct types  of  engine  in  use  to-day  for  power  purposes.  In 


CONCERNING   PRIME    MOVERS.  43 

the  first  place,  engines  with  Corliss  or  equivalent  valve  gear, 
having  separate  admission  and  exhaust  valves  and  running 
at  a  relatively  low  speed,  seldom  over  100  revolutions  per 
minute ;  and,  second,  the  great  group  of  single-valve  engines 
in  which  the  admission  and  exhaust  are  not  independent  of 
each  other,  running  at  speeds  usually  over  200  revolutions 
per  minute,  and  furnished  with  fly-wheel  governors  of  a 


FIG.  17.— GOVERNOR  OF  HIGH-SPEED  ENGINE. 

very  effective  character.  The  choice  between  these  two  kinds 
of  engine  is  somewhat  difficult.  There  are  a  few  excellent 
transition  forms  between  the  types,  but  nearly  every  engine 
with  which  the  reader  is  likely  to  have  to  do  belongs  quite 
distinctly  either  to  one  or  the  other.  As  will  be  shown  later, 
the  slow-speed  engines  with  the  Corliss  valve  gear,  or  its 
equivalent,  utilize  the  steam  rather  more  efficiently  than  any 
single-valve  engine  has  yet  been  able  to  do.  On  the  other 


44 


THE   ELECTRIC    RAILWAY. 


hand,  they  suffer  more  from  condensation  than  high-speed 
engines  of  the  same  capacity  for  doing  work,  on  account  of 
the  greater  size  of  cylinder  necessary  to  compensate  for  the 
decreased  speed.  They  do  not  govern  quite  so  well,  and,  as 
a  class,  do  not  permit  of  admitting  steam  throughout  a  por- 
tion of  the  stroke  anywhere  nearly  as  great  as  that  which  can 
be  reached  with  the  other  mechanisms.  For  electric-railway 
service  these  are  serious  disadvantages,  because  the  load  is 
apt  in  small  roads  to  vary  greatly  and  with  great  rapidity. 

As  the  average  load  on  an  engine  in  an  electric-railway 
power  plant  is  frequently  only  a  quarter  or  a  third  of  the 
maximum  load,  the  slow-speed  engine  is  put  somewhat  at 
a  disadvantage,  for  if  the  engine  is  large  enough  for  the 
maximum  power  required  to  be  developed  within  the  avail- 
able range  of  cut-off,  the  average  power  will  be  developed  at 
a  cut-off  much  too  short  and  an  expansion  of  the  steam  con- 
sequently far  too  great  for  the  highest  economy. 

High-speed  engines,  with  governors  permitting  the  ad- 
mission of  the  steam  during  a  large  part  of  the  stroke,  can 
under  great  variations  of  load  be  worked  on  an  average 
much  nearer  the  ratio  of  expansion  that  corresponds  to  the 
greatest  economy  than  their  low-speed  competitors.  As  a 
class,  however,  they  do  not  utilize  the  steam  as  efficiently. 
If  an  engine  has  to  be  used  in  situations  where  the  changes 
of  load  are  very  violent,  as  in  small  electric  railways,  the 
high-speed  engine  can  usually  be  run  more  economically 
than  even  the  best  Corliss  engines.  If  the  changes  of  load 
are  not  very  rapid  and  relatively  rather  small,  the  latter  type 
of  engine  will  generally  give  the  better  result.  Such  condi- 
tions are  found  now  and  then  in  large  electric  roads  where 
the  number  of  cars  is  so  great  that  the  starts  and  stops  of 
individual  cars  are  not  important  factors  in  change  of  load. 
This  subject  will,  however,  be  more  thoroughly  discussed  in 
the  chapter  on  station  design. 

It  is  important  that  every  man  who  is  to  use  a  steam  engine 

should  understand  thoroughly  how  the  power  it  produces  can 

be   measured.     Ordinarily  an  engine    is   designated   by  its 

available  horse-power,  but  this  practice  really  gives  very  lit- 

e  useful  information  about   the    machine,   and  at  present 


CONCERNING   PRIME    MOVERS.  45 

-makers  either  do  not  specify  the  horse-power,  but  give  the 
dimensions  and  speed,  or  in  mentioning  the  horse-power 
mention  also  the  corresponding  point  of  cut-off  of  the  steam. 
By  one  horse-power,  of  course,  the  reader  will  understand  a 
rate  of  doing  work  equivalent  to  33,000  foot-pounds  per  min- 
ute. This  power  is  derived  from  the  pressure  on  the  piston 
of  the  engine,  and  the  following  almost  self-evident  rule 
gives  the  method  of  finding  the  horse-power  of  any  given 
engine. 

Take  the  area  of  the  piston  in  square  inches,  multiply  it 
by  the  number  of  feet  that  the  piston  travels  each  minute, 
multiply  this  product  by  the  mean  pressure  on  the  piston 
during  its  stroke,  divide  the  entire  product  by  33,000,  and 
the  result  will  be  the  horse-power  of  the  engine  in  question. 
The  area  of  the  piston  in  square  inches  can  be  immediately 
obtained  from  the  bore  of  the  cylinder  as  given  by  the  maker, 
and  the  number  of  feet  of  piston  travel  per  minute  from  the 
stroke  and  the  number  of  revolutions.  The  only  uncertain 
and  troublesome  factor,  then,  is  the  mean  pressure  on  the 
piston. 

If  the  steam  entered  the  cylinder  throughout  the  entire 
stroke,  the  mean  pressure  against  the  piston  would  be  very 
nearly  the  pressure  of  the  steam  in  the  boiler,  and  the  prob- 
lem would  reduce  itself  to  a  pusji  equal  to  the  number  of 
square  inches  in  the  piston  multiplied  by  the  pressure  of  the 
steam  per  square  inch,  and  working  as  many  feet  per  minute 
as  the  piston  travels.  But  inasmuch  as  steam  is  always  used 
expansively,  entering  the  cylinder  at  nearly  boiler  pressure 
and  leaving  it  at  only  a  very  slight  pressure,  the  mean  push 
of  steam  against  the  piston  is  not  so  easy  to  find.  It  is  evi- 
dent, however,  that  if  we  could  measure  the  pressure  of  the 
steam  at  each  point  of  the  piston's  travel,  we  could  get  the 
mean  pressure  at  once,  for  we  should  merely  take  the  press- 
ures at  a  sufficient  number  of  points  and  average  them.  We 
have  fortunately  a  method  of  doing  this  and  ascertaining  at 
the  same  time  a  vast  variety  of  other  valuable  facts  concern- 
ing the  performance  of  the  steam  engine.  This  is  found  in 
the  indicator,  which  is  really  nothing  more  nor  less  than  an 
instrument  for  registering  the  steam  pressure  against  the 


46  THE   ELECTRIC    RAILWAY. 

piston  at  each  point  of  its  path.  So  important  an  instrument 
is  the  indicator  that  no  engineer  is  fit  to  care  for  a  modern 
engine  who  does  not  understand  its  principle  and  use,  and  it 
is  worth  while  devoting  some  little  space  to  the  consideration 
of  the  information  it  can  give  us. 

But  first  let  us  follow  roughly  the  actual  cycle  of  operations 
that  goes  on  in  the  cylinder  of  a  steam  engine,  beginning 
with  the  moment  when  the  valve  that  admits  steam  to  the 
cylinder  opens.  Let  us  suppose  that  we  are  possessed  of  an 
eye  quick  enough  to  follow  the  fluctuations  of  a  steam  gauge 
attached  to  one  end  of  the  cylinder.  The  first  effect,  of 
course,  is  that  steam  at  practically  full  boiler  pressure  rushes 
in,  and  we  should  find  the  steam  gauge  darting  up  to  that 
pressure;  then,  as  the  piston  started  and  the  steam  from  the 
boiler  continued  entering,  the  pressure  would  remain  almost 
exactly  constant  up  to  the  point  of  the  stroke  where  the 
admission  valve  began  to  close.  The  pressure  would  then 
fall,  as  the  steam  in  expanding  and  pushing  on  the  piston 
loses  its  temperature  and  pressure  together.  We  should 
thus  find  the  steam  gauge  sinking  gradually  down  until  very 
near  the  end  of  the  stroke.  Then  as  the  piston  neared  the 
extreme  limit  of  its  motion  the  exhaust  valve  would  open  and 
the  pressure  would  fall  immediately  very  nearly  down  to  that 
of  the  outside  air.  Meaiywhile  the  piston  would  be  on  its 
backward  stroke,  driven  by  the  steam  at  the  other  end  of  the 
cylinder,  and  the  pressure  at  the  end  we  are  investigating 
would  remain,  so  long  as  the  exhaust  port  remained  open, 
very  small  in  amount  and  almost  uniform.  Finally,  as  the 
piston  almost  reached  the  point  where  it  started  the  exhaust 
port  would  close,  and  the  small  amount  of  steam  left  in  the 
cylinder  would  be  slightly  compressed,  until  at  the  end  of  the 
stroke  the  admission  valve  would  open  again,  and  the  press- 
ure would  rise  as  at  first. 

This  is  the  very  cycle  of  operations  that  goes  on  in  either 
end  of  the  cylinder  of  a  steam  engine,  and  it  is  the  duty 
of  the  indicator  to  register  it;  the  instrument,  in  fact,  is 
nothing  more  nor  less  than  a  registering  steam  gauge 
arranged  in  such  form  as  to  be  convenient  for  the  purpose. 
Fig.  1 8  shows  an  excellent  modern  indicator,  and  Fig.  19  a 


CONCERNING    PRIME    MOVERS. 


47 


sectional  view  showing  its  exact  construction.  It  consists, 
primarily,  of  a  cylinder,  seen  at  the  left  of  Fig.  19,  contain- 
ing a  snugly  fitting  piston,  the  upward  motion  of  which  is 
resisted  by  a  spiral  spring;  this  forms  a  true  steam  gauge,  as 
the  compression  of  the  spring  is  exactly  proportional  to  the 


FIG.  18.— THOMPSON  INDICATOR. 


FIG.  19.— SKCTION  OF  THOMPSON  INDICATOR. 


pressure  applied  to  it.  If  we  screw  this  indicator  cylinder 
vertically  into  the  end  of  a  steam-engine  cylinder,  or  to  a 
pipe  communicating  with  it,  and  then  allow  the  engine  to 
run,  the  position  of  the  piston  in  the  indicator  cylinder  will 
depend  on  the  pressure  of  the  steam  applied  to  the  engine 
piston,  and  at  each  moment  of  the  stroke  the  compression  of 
the  spring  will  be  exactly  proportional  to  the  pressure  of  the 
steam  in  the  cylinder  at  that  same  instant.  A  little  piston 
rod  passing  through  the  top  of  this  indicator  cylinder  moves 
a  lever  carrying  at  its  extremity  a  pencil  point.  The  lever  is 
not  a  simple  one,  but  a  combination  of  levers  so  arranged 
that  the  pencil  shall  travel  vertically  up  and  down  instead  of 
in  an  arc.  The  point  of  this  pencil  rests,  as  seen  from  Fig.  18, 
on  the  surface  of  another  cylinder,  over  which,  in  practice,  a 
piece  of  paper  is  tightly  stretched  and  held  in  place  by  the 
pair  of  slender  springs  shown  in  the  cut. 


48  THE   ELECTRIC    RAILWAY. 

If,  now,  the  steam  be  admitted  to  the  engine,  the  pencil 
point  will  fly  up  as  far  as  the  tension  of  the  spring  will  allow 
the  indicator  piston  to  push  it,  and  as  the  steam  expands 
and  the  pressure  falls  the  position  of  the  pencil  in  its  down- 
ward path  will  be  at  every  point  exactly  proportional  to  the 
steam  pressure  in  the  cylinder.  Now  the  cylinder  is  made 
to  revolve  through  nearly  an  entire  revolution ;  by  the  cord 
shown  it  is  attached  to  the  piston  rod  of  the  engine,  so  that 
as  the  piston  moves  the  cylinder  turns  uniformly  under  the 
point  of  the  pencil,  while  a  spring  within  keeps  the  cord  taut 
and  takes  up  the  slack  on  the  back  stroke,  so  as  to  bring  the 
cylinder  exactly  back  to  its  starting-point.  The  effect  of  this 
arrangement  is  as  follows :  The  position  of  the  pencil  point 
in  a  vertical  line  is  always  proportional  to  the  pressure  in  the 
steam  cylinder ;  its  position  with  reference  to  the  rotation  of 
the  cylinder  is  always  proportional  to  the  distance  through 
which  the  piston  of  the  engine  has  moved,  so  that  the  press- 
ure in  the  steam  cylinder  at  every  point  of  the  piston  stroke 
is  registered  upon  the  paper  stretched  on  the  revolving  drum. 
On  taking  off  the  paper  and  unrolling  it,  it  is  possible  at  once 
to  see  exactly  how  the  pressure  has  varied  throughout  the 
stroke;  and  if  the  pressure  required  to  produce  a  given  com- 
pression of  the  spring  in  the  indicator  be  known,  we  can  also 
tell  by  the  heights  at  various  points  of  the  indicator  diagram 
just  the  steam  pressure  in  pounds  per  square  inch  that  was 
exerted  on  the  piston. 

With  every  indicator  are  furnished  two  or  three  springs 
of  strengths  accurately  known,  and  graduated  so  that  each 
inch  of  motion  of  the  pencil  point  shall  correspond  to  an 
exact  number  of  pounds  pressure  on  the  spring.  A  valve  is 
inserted  between  the  indicator  and  the  steam  cylinder,  so 
that  the  piston  of  the  instrument  will  not  be  in  motion  except 
at  the  moment  when  it  is  desired  to  trace  an  indicator 
diagram.  As  an  added  precaution  against  injury  to  the 
indicator  a  little  handle,  shown  at  the  top  of  the  indicator 
cylinder,  enables  the  upper  portion  of  it  to  be  turned  so  as 
to  draw  the  pencil  away  from  the  paper  except  when  it  is 
wanted.  As  the  stroke  of  most  engines  is  greater  than  the 
periphery  of  the  indicator  drum,  the  latter  is  usually  attached 


CONCERNING    PRIME    MOVERS.  49 

to  the  piston  rod,  or  its  cross-head,  through  the  medium  of  a 
reducing  motion  of  some  sort,  frequently  a  pendulum  arrange- 
ment, of  which  the  lower  extremity  is  operated  by  the  cross- 
head  of  the  engine,  while  the  cord  to  the  indicator  is  attached 
to  an  arc  further  up  toward  the  center  of  motion.  It  should 
always  be  remembered,  however,  in  arranging  anything  of 
this  kind  that  it  must  be  so  put  together  that  the  motion  im- 
parted to  the  indicator  drum  shall  be  exactly  proportional  to 
that  of  the  cross-head.  For  details  of  the  practical  adjustment 
of  the  indicator  it  is  best  to  refer  to  one  of  the  excellent  trea- 
tises upon  it,  or  to  the  plain  working  directions  that  are  fur- 
nished by  the  makers  of  indicators,  as  an  elaboration  of  this 
sort  of  thing  is  hardly  within  the  scope  of  the  present  chapter. 
On  admitting  the  steam  to  our  indicator  and  pressing  the 
pencil  down  lightly  against  the  drum  during  a  single  com- 
plete stroke  by  means  of  the  little  handle  before  alluded 
to,  a  tracing  of  the  indicator  diagram  will  be  obtained,  and 
its  general  shape  will  be  that  shown  in  Fig.  20.  In  this 
diagram  the  line  F  A  represents  the  rise  in  pressure  as  the 
admission  valve  is  opened,  and  the  line  A  B  shows  the 


FIG.  20.— SPECIMEN  INDICATOR  CARD. 

period  during  which  steam  is  freely  admitted  to  the  cylin- 
der and  the  pressure  kept  constant;  the  smooth  curve 
B  C  shows  the  gradually  falling  pressure  as  the  steam 
expanded  up  to  the  point  where,  at  C,  the  exhaust  port  be- 
4 


5Q  THE   ELECTRIC    RAILWAY. 

gins  to  open;  from  C  to  D  the  pressure  falls  to  a  minimum, 
and  continues  constant  along  the  backward  stroke  up  to  E, 
where  the  exhaust  port  closes,  and  the  small  amount  of  steam 
that  remains  is  slightly  compressed  until  the  opening  of  the 
admission  valve.  The  object  of  this  compression  is  to  cushion 
the  motion  of  the  piston  slightly,  so  as  to  prevent  too  violent 
strains  upon  the  engine.  In  taking  an  indicator  diagram  it 
is  customary  to  turn  one  of  the  valves  of  the  instrument  so  as 
to  admit  the  outside  air  to  the  indicator  cylinder  before  steam 
is  turned  upon  it;  then,  the  drum  being  in  motion,  the  pen- 
cil point  is  swung  against  it,  and  a  single  line  showing  the 
position  of  the  spring  for  atmospheric  pressure  drawn  near 
the  bottom  of  the  paper.  This  furnishes  a  point  of  reference 
both  for  showing  the  exact  length  of  the  indicator  diagram 
and  the  pressure  of  the  steam  above  that  of  the  atmosphere. 

Now,  having  the  indicator  card  taken,  the  first  use  to  which 
we  can  put  it  is  the  determination  of  the  average  pressure  of 
steam  on  the  piston  for  the  purpose  of  finding  the  horse- 
power by  the  process  indicated  previously. 

The  simplest  way  of  obtaining  this  mean  pressure  is  to  erect 
at  right  angles  to  the  atmospheric  line  ten  pencil  lines  at 
equal  distances  from  each  other,  one  being  at  each  end  of  the 
diagram,  then  measure  the  lengths  of  each  of  these,  add 
them  together  and  divide  by  10;  then  the  quotient  in 
inches  represents  the  mean  pressure  on  the  piston  reckoned 
on  the  scale  of  the  spring  that  is  used.  If  the  indicator 
spring  gives  a  motion  of  one  inch  at  the  pencil  point  for  fifty 
pounds,  and  the  mean  of  the  vertical  heights  be  one  inch, 
fifty  pounds  will  be  the  mean  pressure  per  square  inch  which 
has  to  be  used  in  computing  the  horse-power.  A  far  more 
accurate  way  of  obtaining  the  true  mean  pressure  is  to 
measure  the  area  of  the  entire  diagram  by  means  of  a  plani- 
meter,  a  little  instrument  made  especially  for  the  purpose; 
then  divide  the  area  in  inches  by  the  length  in  inches,  and 
the  mean  pressure  is  at  once  found.  The  planimeter  is  not 
always  at  hand,  however,  and  the  other  method  gives  a  toler- 
able approximation. 

In  the  next  place,  suppose  the  piston  of  the  engine  does 
it  well  and  the  steam  leaks  past  it:  the  result  will  be, 


CONCERNING    PRIME    MOVERS.  51 

evidently,  that  the  pressure  behind  the  piston  will  lessen 
very  rapidly,  and  consequently  on  the  indicator  diagram  the 
line  B  C  will  fall  toward  the  atmospheric  line  much  more 
rapidly  than  in  the  figure  given.  If,  on  the  contrary,  the 
piston  is  tight  but  the  steam  admission  valve  leaks,  the  press- 
ure will  not  fall  by  any  means  rapidly  enough.  If  the  steam 
is  only  admitted  for  a  very  small  portion  of  the  stroke,  and 
there  is  considerable  condensation  in  the  cylinder,  the  press- 
ure will  again  fall  too  rapidly. 

If  the  valves  do  not  open  and  close  at  the  proper  time  the 
result  will  be  at  once  seen  in  the  indicator  card.  For  exam- 
ple :  Fig.  2 1  shows  a  card  taken  from  a  well-built  modern 


FIG.  21.— INDICATOR  CARD— VALVES  WRONGLY  SET. 

engine  in  which  the  valves  were  not  set  correctly ;  the  vertical 
line  at  the  left  shows  on  the  scale  used  for  the  diagram  the 
full  boiler  pressure.  The  admission  valve,  as  will  be  seen 
from  the  sluggish  rise  of  pressure,  only  opens  after  the  piston 
lias  started  on  its  trip ;  the  steam  pressure  never  catches  up 
effectively  with  the  piston,  and  steam  does  not  enter  the  cyl- 
inder as  freely  as  it  should,  although  after  the  valve  is  wide 
open  the  pressure  has  risen  a  little.  The  line  showing  the 
expansion  of  the  steam  does  not  look  promising,  and  the 
pointed  toe  of  the  diagram  shows  that  the  exhaust  port  was 
very  late  in  opening,  for  the  pressure  did  not  fall  anywhere 
near  the  atmospheric  pressure  until  the  piston  was  well 
started  on  its  backward  stroke.  Besides  opening  too  late, 
the  exhaust  port  closed  too  late,  so  that  there  was  not  the 
slightest  cushioning  at  the  point  where  the  admission  valve 


52  THE   ELECTRIC    RAILWAY. 

began  its  rather  slow  opening  motion.     Fig.  22  shows  the 
same  diagram  after  the  valves  had  been  reset  by  reference 


FIG.  22.— INDICATOR  CARD— VALVES  READJUSTED. 

to  the  indicator  card.  You  will  see  that  in  the  first  place  the 
boiler  pressure  is  utilized  much  more  fully,  the  expansion 
gives  a  much  smoother  curve,  and  the  steam  is  expanded 
far  more  nearly  down  to  the  atmospheric  line. 

The  exhaust  is  apparently  not  quite  free  enough,  but  the 
exhaust  valve  opens  and  closes  earlier,  so  that  there  is  a 
slight  cushioning  at  the  end  of  the  stroke,  and  when  the 


FIG.   23-CARD  FROM  COMPOUND  CONDENSING   ENGINP,  HIGH-PRESSURE  CYLINDER. 

admission  valve  opens  it  moves  rapidly  and  opens  fully,  so 
that  the  steam  pressure  rises  sharply  and  is  fairly  well  main- 
tained. Figs.  23  and  24  show  two  very  perfect  indicator  dia- 


CONCERNING   PRIME    MOVERS.  53 

grams  taken  from  a  compound  Corliss  pumping  engine. 
Fig.  23  is  the  high-pressure  diagram  and  Fig.  24  the  low- 
pressure.  In  the  latter,  of  course,  the  atmospheric  line  cuts 
through  the  diagram  as  the  engine  was  condensing,  and  the 
pressure  consequently  fell  below  the  atmospheric  pressure. 
In  the  former  of  these  diagrams  the  proper  working  of  the 
valves  is  very  elegantly  shown.  The  steam  pressure  rises 
almost  up  to  full  boiler  pressure  instantly,  and  is  maintained 
almost  absolutely  constant  until  the  admission  valve  closes. 
The  expansion  line  of  the  steam  is  almost  perfect,  and  when, 
just  at  the  end  of  the  stroke,  the  exhaust  valve  opens,  it 
opens  fully  and  drops  the  pressure  to  a  nearly  constant 


FIG.  24.— CARD  FROM  COMPOUND  CONDENSING  ENGINE,  LOW-PRESSURE  CYLINDER. 

amount,  where  it  remains  until  the  exhaust  port  closes,  and 
produces  a  slight  cushioning  at  the  end  of  the  stroke. 

The  diagram  from  the  low-pressure  shows  almost  the  same 
beautiful  characteristics.  The  admission  line  is  vertical  and 
turns  sharply  at  the  top  into  the  steam  line.  The  steam 
admitted,  however,  falls  off  somewhat  in  pressure,  inasmuch 
as  it  comes  not  from  the  boiler,  but  from  the  high-pressure 
cylinder.  The  expansion  line  is  as  perfect  as  in  the  previous 
diagram,  and  the  exhaust  works  with  the  same  beautiful 
promptness.  Altogether,  these  are  model  diagrams.  The 
engine  from  which  they  were  taken  has  a  high-pressure  cyl- 
inder 1 5  inches  in  diameter  and  a  low-pressure  30  inches  in 
diameter,  both  of  3O-inch  stroke.  The  high-pressure  cylinder 
takes  steam  at  125  pounds.  The  engine  makes  46  revolu- 


THE   ELECTRIC    RAILWAY. 


tions  per  minute,  and  the  consumption  of  coal  is  but  1.8 
pounds  per  horse-power  per  hour,  a  result  very  seldom 
approached  in  stationary  engines  of  this  size.  Pigs.  2  5  and  26 
show  a  pair  of  excellent  cards  taken  from  an  Armington  & 
Sims  engine  with  a  single  piston  valve,  such  as  was  shown 


FIG.  25.— CARD  FROM  SINGLE-VALVE  ENGINE.    HEAVY  LOAD.     , 

in  the  early  part  of  this  chapter.  The  present  diagrams 
show  perhaps  as  good  results  as  can  be  obtained  from  this 
class  of  valves  in  actual  practice.  In  this  case  the  admission 
line  of  the  steam  is  vertical,  and  runs  almost  up  to  full  boiler 
pressure;  the  expansion  curve  will  be  seen  to  be  somewhat 
waved,  owing  possibly  to  the  slight  irregularity  of  motion 
in  the  pencil  of  the  indicator,  from  the  very  high  speed  at 
which  the  apparatus  is  worked. 

The  cylinder  was  9  1-2  by  12  inches,  the  speed  200  revolu- 


FIG.  26.— CARD  FROM  SINGLE-VALVE  ENGINE.    LIGHT  LOAD, 

tions  per  minute,  with  steam  at  85  pounds.  The  noticeable 
feature  of  the  cards  from  this  and  nearly  all  other  high- 
speed engines  is  the  relatively  large  amount  of  compres- 
sion, the  exhaust  port  closing  rather  early  in  the  stroke; 


CONCERNING   PRIME    MOVERS.  55 

especially  is  this  true  when,  as  in  Fig.  26,  the  load  on  the 
engine  is  exceedingly  light,  hardly  more  than  the  friction  of 
the  moving  parts.  In  this  case  the  compression  begins 
almost  at  half  stroke,  the  cut-off  of  the  steam  admitted  being 
very  early  in  the  stroke.  These  cards  are  most  excellent  for 
a  high-speed  engine,  but  do  not  show  the  economy  of  steam 
of  the  pair  of  cards  just  given.  The  expansion  of  the  steam 
and  the  operation  of  the  exhaust  valve  fail  to  give  the  good 
result  that  is  obtained  by  the  use  of  separate  admission  and 
exhaust  valves. 

Fig.  27  shows  an  indicator  card  of  a  somewhat  less  desir- 
able kind  taken  from  an  engine  actually  engaged  in  driving 
an  electric-railway  plant.  In  this  machine  the  valves  were 
not  adjusted  anywhere  nearly  as  well  as  in  the  example  just 
given.  The  compression  begins  very  early  in  the  stroke  and 
runs  insensibly  into  the  admission  line ;  the  steam  line  falls 


FIG.  27.— CARD  FROM  SINGLE-VALVE  ENGINE  IN  RAILWAY  POWER  STATION. 

off  in  a  curve,  leaving  the  point  where  the  admission  valve 
closed  rather  indefinite.  The  expansion  curve  is  bad  and 
the  opening  of  the  exhaust  valve  rather  gradual.  All  this 
means  lack  of  economy,  for  neither  is  steam  admitted  at  as 
high  an  average  pressure  as  is  desirable,  nor  is  it  expanded 
properly  before  the  exhaust  begins  to  open ;  besides  this,  the 
compression  is  much  larger  than  is  ordinarily  desirable. 

High-speed  engines  seldom  give  indicator  diagrams  show- 
ing anything  like  the  efficiency  found  in  using  some  other 
forms  of  valve  gear;  nevertheless,  the  practice  in  this  respect 
is  improving,  and  some  of  the  modern  engines  give  very 
good  results.  At  all  events,  the  difference  between  the  two 
classes  is  not  nearly  so  formidable  as  it  once  was.  The  weak 
point  of  the  low-speed  engine  has  already  been  mentioned — 
the  relatively  large  cylinder  and  consequent  internal  waste, 
lack  of  range  of  cut-off,  and  sluggish  governing.  The  weak 


56  THE   ELECTRIC    RAILWAY. 

point  of  the  high-speed  engine  with  its  single  valve  is  that 
the  steam  is  not  used  as  effectively  because  of  the  inter- 
dependence of  all  the  movements  of  the  valve.  If  the  cut-off 
is  changed  the  action  of  the  admission  and  exhaust  is  changed 
throughout,  with  the  result  that  in  most  cases  the  steam  is 
not  admitted  freely  up  to  full  boiler  pressure,  the  exhaust  is 
apt  to  take  place  at  the  wrong  time,  and  there  is  often  an 
objectionable  amount  of  compression.  All  these  mean  that 
the  steam  is  not  used  in  the  way  to  secure  the  maximum 
efficiency,  and  the  difference,  rather  evident  from  an  inspec- 
tion of  the  indicator  cards,  is  often  seen  in  the  respective 
coal  bills  met  in  using  these  two  types  of  machine. 

When  economically  run,  the  modern  high-speed  engine 
will  produce  one  horse-power  per  hour  with  a  trifle  over  30 
pounds  of  steam,  seldom  or  never  below  that  figure.  An 
engine  fitted  with  Corliss  or  equivalent  valve  gear,  and  of 
similar  size,  will,  under  favorable  conditions,  do  the  same  work 
with  the  expenditure  of  27  to  30  pounds  of  steam.  Other 
things  being  equal,  large  engines  are  rather  more  economical 
than  small  ones.  If  compound  engines  are  employed,  used 
non-condensing,  the  consumption  of  water  per  horse-power 
hour  is  usually  from  22  to  26  pounds;  if  used  condens- 
ing, from  1 6  to  20.  Condensation  in  either  simple  or  com- 
pound engines  is  likely  to  save  something  like  1 5  per  cent,  of 
the  fuel.  Very  large  triple-expansion  condensing  engines  may 
produce  the  horse-power  hour  on  as  low  as  12  or  13  pounds 
of  steam,  but  such  figures  are  rather  unusual.  These  data 
can,  of  course,  be  regarded  only  as  approximations,  as  the 
results  obtained  are  influenced  by  the  care  exercised  in  set- 
ting the  valves  of  the  engine  to  do  the  most  economical  work. 
For  example,  in  Figs.  21  and  22  the  changes  made  in  the 
valve  motion  reduced  the  amount  of  fuel  per  day  from  16 
tons  to  12  tons  for  the  same  work,  which  of  itself  is  a  suffi- 
cient lesson  in  the  importance  of  using  the  indicator  and 
working  the  engine  in  the  very  best  manner  of  which  it  is 
capable. 

In  choosing  an  engine  for  operating  an  electric-railway 
power  station  very  many  things  have  to  be  taken  into  consid- 
eration ;  the  general  principle  to  follow,  however,  is  to  em- 


CONCERNING   PRIME    MOVERS.  57 

ploy  an  engine  of  such  size  and  character  that  it  can  be  worked 
with  its  average  load  at  nearly  its  maximum  point  of  economy. 
With  large  roads,  where  the  load  does  not  vary  very  much, 
these  conditions  can  be  fulfilled  admirably  by  large  Corliss  or 
similar  engines,  either  simple  or  compound.  If,  however,  the 
load  is  likely  to  vary  excessively,  and  the  maximum  load  will 
probably  be  three  or  four  times  the  average  load,  such 
engines  if  used  will  be  so  seriously  underloaded  as  to  be  really 
less  economical  than  the  high-speed  engines,  which,  although 
intrinsically  less  effective  in  their  use  of  steam,  more  than 
make  up  for  this  loss  in  their  greater  range  of  power  and 
consequent  ability  to  handle  heavy  loads  on  occasion,  while 
on  the  average  working  near  their  point  of  maximum  effi- 
ciency. This  principle  will  be  elaborated  further  in  the  chap- 
ter on  station  design. 

A  very  large  portion  of  this  chapter  has  been  devoted  to 
the  steam  engine  because  it  is  at  present,  and  is  likely  to  be 
for  some  time  to  come,  the  principal  prime  mover  for  elec- 
trical power  stations,  especially  electric  railways.  Gas 
engines,  which  have  been  before  alluded  to,  and  water- 
wheels,  of  which  we  will  now  speak,  are  occasionally  used  for 
such  purposes.  The  difficulty  of  governing  under  a  very 
variable  load  is  so  great  that  the  advantage  of  cheap  power 
rendered  available  by  these  means  is  materially  lessened.  In 
speaking  of  water-wheels,  text-books  and  popular  treatises 
generally  begin  by  a  formal  mention  of  overshot  and  breast 
wheels,  both  vertical  wheels  on  which  the  water  acts  partly 
by  weight  and  partly  by  impulse,  and  finally  give  some  brief 
mention  of  turbine  water-wheels.  At  the  present  time  the 
latter  constitute  the  only  class  worth  the  slightest  discussion 
for  our  particular  purposes,  with  the  exception  of  a  peculiar 
form  of  impulse  wheel  frequently  used  for  enormously  high 
heads  of  water. 

The  overshot,  breast  and  undershot  wheels  are  almost 
as  obsolete  to-day  as  single-acting  engines  and  steam 
pressures  of  1 5  pounds  per  square  inch.  The  turbine  is  a 
water-wheel  generally,  but  not  always,  arranged  on  a  ver- 
tical axis,  and  receiving  and  discharging  water  in  various 
directions  around  its  circumference.  It  differs  from  all  other 


THE   ELECTRIC    RAILWAY. 


water-wheels  in  that  all  the  vanes  or  paddles  provided  are 
acted  on  simultaneously  instead  of  portions  of  the  periphery 
being  used  in  succession.  The  wheel  consists  in  general  of 
a  drum  or  annular  passage  containing  a  set  of  curved  vanes 
shaped  in  such  a  manner  that  the  water,  after  glancing  from 
them,  is  left  behind  with  a  minimum  amount  of  energy. 
They  have  the  great  advantage  of  being  of  very  small  bulk 
for  their  power  and  being  equally  efficient  for  quite  high  and 
low  heads  of  water.  On  such  wheels  the  water  acts  by  vir- 
tue of  its  weight  and  velocity,  and  the  supply  is  received 
either  directly  from  a  reservoir,  in  which  case  the  wheel  is 
placed  close  to  an  opening  in  its  bottom,  or  through  a  supply 
pipe  and  wheel  case.  The  former  method,  involving,  as  it 
does,  no  loss  from  friction  in  pipes,  is  preferable  for  low  falls ; 
the  latter  for  considerable  heads.  In  most  turbines  the  open- 


FIG.  28.— PARALLEL-FLOW  TURBINE. 


FIG.  29.— ARRANGEMENT  OF  GUIDE  VANES. 
PARALLEL-FLOW  TURBINE. 


ing  through  which  the  water  rushes  upon  the  wheel  is  fur- 
nished with  guide  blades  to  give  the  stream  the  most  effective 
direction.  Turbine  water-wheels  are  generally  divided  into 
three  classes,  according  to  the  manner  in  which  the  water 
acts  upon  them.  First,  the  parallel-flow  turbines,  in  which  the 
water  is  supplied  and  discharged  in  a  current  parallel  to  the 
axis  of  the  wheel;  second,  outward-fiow  turbines,  in  which 
the  water  is  supplied  and  discharged  in  currents  radiating 
from  the  axis;  and,  third,  inward-flow  turbines,  in  which  the 
water  is  supplied  at  the  periphery  and  discharged  through 
the  center.  To  these  may  be  added  the  modern  class  of  hori- 
zontal turbines,  in  which  the  turbine  principle  is  used  in 
Is  upon  a  horizontal  shaft,  thus  avoiding  the  necessity  of 
-earing.  These  may  belong  to  any  one  of  the  three  classes 
above  mentioned.  Turbines  frequently  work  "drowned," 


CONCERNING    PRIME    MOVERS.  59 

that  is,  entirely  submerged;  but  inasmuch  as  some  efficiency 
is  lost  in  this  way,  the  practice  is  not  to  be  generally  rec- 
ommended. 

Fig.  28  gives  a  diagrammatic  view  of  a  parallel-flow  tur- 
bine, and  the  accompanying  Fig.  29  shows  the  way  in  which 
the  guide  blades  and  vanes  are  arranged  to  produce  the  proper 
reaction.  The  water  enters  the  guide  blades  around  the 
periphery  of  the  casing,  and  from  these  passes  to  the  wheel 
itself,  putting  it  in  powerful  rotation.  The  drum  A  is  a  sup- 
ply chamber,  containing  the  guide  blades;  B  is  the  wheel 
proper.  Fig.  30  shows  a  horizontal  portion  of  an  outward- 
flow  turbine  wheel ;  A  is  a  supply  chamber  in  the  interior, 
being  in  the  form  of  a  vertical  cylinder,  with  a  ring  of  open- 
ings around  its  lower  end ;  C  shows  the  guide  blades  corres- 
ponding to  those  in  the  figures  previously  shown,  and  D  the 


FIG.  30.— DIAGRAM  OF  OUTWARD-FLOW  FIG.  31.— DIAGRAM  OF  INWARD-FLOW 

TURBINE.  TURBINE. 

buckets  of  the  wheel.  Passing  to  the  inward-flow  turbine, 
Fig-  3 i  gives  a  similar  diagram  for  it.  The  water  is  led,  as 
in  the  outward-flow  turbine,  by  a  vertical  chamber;  B  is  the 
wheel,  provided  with  vanes  D  D  and  free  to  discharge  its 
water  through  the  centre ;  C  is  one  of  the  guide  blades  to 
direct  the  water  against  the  vanes.  Fig.  32  gives  a  view 
of  a  horizontal  inward-flow  turbine,  showing  how  these  gen- 
eral principles  are  applied  in  a  modern  wheel  often  used  for 
electrical  purposes.  The  efficiency  of  all  these  wheels  is 
about  the  same,  and.  equals  say  80  per  cent,  of  the  theoretical 
energy  of  the  water  as  it  strikes  the  wheel.  No  simple  rules 
can  be  given  for  computing  the  water-power  of  a  given  fall, 
as  the  data  regarding  the  velocity  and  amount  of  water  can- 
not be  readily  ascertained  without  a  careful  survey,  which 
should  be  made  by  a  qualified  engineer.  The  general  prin- 


60  THE   ELECTRIC    RAILWAY. 

ciple  of  supply,  however,  is  to  utilize  as  high  a  fall  as  prac- 
ticable with  as  little  intervening  pipe  as  possible, 
horizontal  turbine  is  rather  a  favorite  on  account  of  the  con- 
venient position  of  the  main  shaft.  Turbine  water-wheels 
not  only  are  enormously  powerful  in  proportion  to  their  bulk, 
but  have  a  very  high  velocity  of  rotation ;  so  great,  in  fact, 
that  in  some  large  electric  stations  the  dynamos  are  belted 
direct  to  the  water-wheels,  but  furnished  with  larger  pulleys, 
the  speed  of  the  wheels  being  actually  greater  than  that  desired. 
Where  water-power  can  be  cheaply  had  it  is  generally 


FIG.  32.— A  TYPICAL  HORIZONTAL  TURBINE  (LEFFEL  FORM). 

advantageous  to  use  it,  and  in  certain  localities,  where  fuel 
is  very  dear,  the  use  of  water  is  almost  imperative;  but 
it  must  not  be  forgotten  that  there  are  circumstances  under 
which  no  advantage  can  be  gained  over  steam.  It  is  prob- 
able that  the  water-wheel  will  be  used  more,  rather  than  less, 
for  electrical  power  purposes,  as  there  are  many  parts  of  the 
country  where  fuel  is  particularly  expensive,  and  by  the 
transmission  of  power  for  a  few  miles,  water-falls  can  be 
utilized  with  the  greatest  advantage.  With  the  electro-motive 
force  at  present  used  for  railway  work,  the  distance  of  prac- 
tical transmission  is  somewhat  limited  ;  but  there  are  cases  in 
which  it  might  even  be  worth  while  to  supply  power  from  a 
distant  dynamo  at  a  very  high  potential  for  driving  a  railway 


CONCERNING    PRIME    MOVERS. 


Cl 


power  station  at  the  usual  electro-motive  force.  The  prin- 
cipal disadvantage  of  the  water-wheel  is  the  difficulty  of  gov- 
erning it.  This  difficulty  is  real  and  great,  and  arises  from 
the  large  mass  of  falling  water  that  has  to  be  controlled,  and 
the  consequent  mass  and  inertia  of  the  gates.  The  result  of 
this  is  that  a  water-power  governor  lacks  sensitiveness,  and 
it  is  only  with  great  difficulty  that  the  wheel  can  be  held  at 
constant  speed.  This  is  of  course  a  serious  objection  for 
electric  uses,  and  more  especially  so  where  the  load,  as  in 
electric  railways,  may  vary  with  great  rapidity.  All  the 
disadvantages  of  bad  governing  in  engines  are  exaggerated 
when  these  are  replaced  by  water- wheels,  because  the  gov- 
ernor does  not  act  so  quickly  nor  is  it  so  effective  a  regulator 


FIG.  33.-FOOTE  SPEED  REGULATOR. 

as  the  isochronous  governor  of  a  steam  engine.  Neverthe- 
less, on  occasion,  good  work  can  be  done  with  water-wheels. 

There  are  ingenious  electrical  devices  for  controlling  the 
flow  of  water  at  a  distant  point  by  a  governor  at  the  water- 
wheel  ;  and  there  is  at  least  one  speed  regulator  that  obviates 
the  necessity  for  a  sensitive  governor  at  the  wheel  by  regu- 
lating the  speed  of  the  driven  dynamo,  irrespective,  within 
certain  limits,  of  the  velocity  of  rotation  of  the  driving  pulley. 

The  Foote  speed  regulator,  shown  in  Fig.  33  is  an  apparatus 
for  accomplishing  this  end  that  has  met  with  considerable 
favor  in  electric  light  and  power  stations.  The  prime  mover 
is  belted  to  a  pulley,  shown  on  the  left-hand  end  of  the 


62  THE    ELECTRIC    RAILWAY. 

regulator,  while  the  dynamo  is  belted  to  the  larger  pulley  at 
the  other  end.  The  condition  for  operation  is  that  the  driving- 
shaft  shall  have  a  speed  greater  at  all  times  than  that  of  the 
driven  shaft.  The  large  central  drum  has  around  its  periph- 
ery friction  brakes  adjusted  by  the  centrifugal  governor. 
The  brake  shoes  are  of  sheet  steel,  with  a  layer  of  paper  pads 
that  fit  closely  on  the  surface  of  the  friction  pulley ;  they  are 
pressed  down  upon  it  by  means  of  the  levers  shown,  and 
actuated  by  the  coiled  spring  on  the  shaft  just  at  the  right  of 
the  drum.  The  tension  can  be  changed  by  means  of  a  screw 
collar,  and  the  controlling  device  is  the  centrifugal  governor, 
the  pressure  of  which  counteracts  that  of  the  spring  when  the 
machine  is  in  motion.  When  the  driving  pulley  is  running 
faster  than  the  required  speed  the  arms  of  the  automatic  gov- 
ernor are  thrown  out  by  the  centrifugal  governor,  and  par- 
tially release  the  pressure  of  the  brake  shoes  on  the  friction 
wheel,  so  that  enough  slipping  ensues  to  keep  the  driven 
shaft  at  its  proper  speed.  If  the  load  on  the  dynamo  varies 
enough  to  cause  the  slightest  decrease  of  speed  the  governing 
weights  fall  toward  the  shaft  and  the  brake  shoes  gripe  the 
friction  pulley  more  closely.  Of  course  such  a  regulator  is 
at  its  best  when  the  variations  of  speed  are  not  great,  and 
it  is  in  successful  use  in  a  number  of  water-power  elec- 
tric light  and  power  stations.  For  railway  wrork  such  an 
apparatus  may  sometimes  prove  desirable,  and  would  doubt- 
less be  effective  in  keeping  the  speed  nearly  constant  unless 
the  changes  of  load  were  exceptionally  violent. 

Before  closing  this  brief  mention  of  water-wheels,  one 
should  be  mentioned  that  has  made  a  remarkable  name  for 
itself  in  service  under  certain  peculiar  conditions.  This  is 
the  Pelton  water-wheel  shown  in  Fig.  34.  It  is  purely  a  jet 
wheel,  acting  by  the  tremendous  impulse  of  a  water  jet  under 
a  powerful  head.  The  buckets,  as  will  be  seen  at  a  glance, 
are  numerous,  small,  and  doubly  concave,  sweeping  gradually 
away  from  a  ridge  in  the  center;  this  is  for  the  purpose  of 
allowing  the  water  jet  to  divide  and  move  smoothly  off  to  the 
sides  instead  of  spattering,  as  would  be  the  case  if  it  impinged 
on  a  flat  or  smoothly  concave  vane.  These  wheels  are  made 
in  a  single  massive  casting,  with  buckets  bolted  firmly  to  the 


CONCERNING    PRIME    MOVERS.  63 

periphery,  and  have  proved  very  successful  where  an  im- 
mense head  of  water  is  to  be  utilized.  They  are  not  employed 
for  replacing  turbines  under  ordinary  conditions,  but  where  a 
small  quantity  of  water  under  a  very  large  head  is  available 
the  Pelton  wheel  is  almost  the  only  one  that  has  in  practice 
given  a  thoroughly  good  account  of  itself.  It  is  in  use  already 
in  a  number  of  power-transmission  plants  in  and  about  the 
Rocky  Mountains  and  on  the  Pacific  coast,  and  replaces  the 
turbine  with  admirable  effect  when  the  head  of  water  amounts 


FIG.  34.— PELTON  WATER-WHEEL. 

to  a  hundred  feet  or  more.     Its  efficiency  is  quite  equal  to 
that  of  the  best  overshot  or  turbine  wheels. 

Wherever  good  water-power  is  available  it  is  certainly  well 
worth  investigation  as  a  source  of  power  for  electrical  enter- 
prises in  the  vicinity.  To  decide  on  its  ability  to  compete 
successfully  with  steam  may  not  always  be  easy,  but  it  is 
worth  while  to  make  careful  estimates  whenever  there  is 
a  reasonable  chance  of  good  results,  from  the  use  of  water- 
power.  Under  favorable  circumstances  its  advantage  of 
great  cheapness  is  obvious ;  its  principal  disadvantage  is  the 
difficulty  of  proper  governing,  although  this  can  be  some- 
what reduced  by  proper  design  of  the  station  and  by  govern- 
ing appliances  such  as  those  mentioned. 


CHAPTER  III. 

MOTORS    AND    CAR    EQUIPMENT. 

To  drive  a  shaft  when  speed  and  load  are  desired  to  vary 
both  widely  and  independently  is  the  work  of  the  electric- 
railway  motor. 

As  to  variation  of  speed,  it  has  already  been  explained  that 
in  the  design  of  a  dynamo  electric  machine,  or  in  the  com- 
parison of  one  motor  with  another,  variation  in  the  number 
of  armature  loops  must  be  considered  as  affecting  the  speed, 
other  things  being  equal.  But  in  studying  the  action  of  any 
particular  motor,  when  finally  in  operation,  this  cause  of 
speed  variation  may  be  neglected,  since  the  armature,  once 
wound,  carries  in  the  magnetic  field  at  all  times  the  same 
number  of  conductors.* 

The  other  quantities,  changes  in  which  are  connected  with 
changes  in  speed,  are  (i)  strength  of  field,  (2)  the  rate  of 
work,  i.e.,  the  quantity  of  work  done  in  a  given  time.  As 
has  been  already  shown,  the  rate  of  work  is  measured  by  the 
product  of  (3)  the  current,  and  (4)  the  counter  electromotive 
force.  The  current,  however,  is  readily  expressed  in  terms 
of  the  counter  E.  M.  F.,  the  resistance  of  the  machine,  and 
the  applied  electromotive  force,  since  it  is  always  such  a  cur- 
rent as  will  flow  over  the  given  resistance  under  a  pressure 
equal  to  the  difference  between  the  two  opposing  pressures, 
- — that  applied  or  impressed  by  the  dynamo  through  the  line, 
and  that  generated  by  the  motor  armature  itself.  (5)  As 
seen  from  the  above,  change  in  the  applied  E.  M.  F.  is  also 
connected  with  change  in  the  speed.  The  quantities  (i),  ^2), 
(3),  (4)  and  (5)  are  interdependent,  but  are  separately  men- 

*  It  is  of  course  possible  to  devise  mechanism  such  that,  in  connection  with  the  com- 
mutator, it  would  afford  a  means  of  changing  at  will  the  number  of  active  loops,  but, 
thus  far.  practice  has  not  justified  such  a  complication.  We  may,  therefore,  in  examin- 
ing the  action  of  a  railway  motor,  take  the  number  of  armature  wires  moving  in  the  field 
as  constant. 

64 


MOTORS  AND  CAR  EQUIPMENT.  65 

tioned,  since  convenience  requires  reference  first  to  one,  then 
to  another. 

Of  these  five  quantities,  perhaps  that  which  in  practice  is 
most  constant  is  strength  of  field.  As  has  been  shown 
(Chapter  I . ) ,  the  efficiency  of  a  motor  depends  upon  the  relation 
of  the  counter  E.  M.  F.  to  the  applied  E.  M.  F.  High  effi- 
ciency, or  relatively  high  counter  E.  M.  F.,  is  desirable  at 
any  and  all  speeds.  But  high  counter  E.  M.  F.  goes  with  a 
large  product  of  the  three  factors,  (a)  number  of  armature 
loops,  (b]  speed  of  rotation,  and  (r)  strength  of  field.  As 
noted,  (a]  the  number  of  loops  is  fixed;  (b}  the  speed  is  lim- 
ited by  practical  requirements,  hence  (c)  great  strength  of 
field  is  constantly  desirable.  It  is  therefore  good  practice  so 
to  wind  a  street-railway  motor,  by  putting  a  relatively  large 
number  of  turns  around  its  magnets,  that  a  maximum 
strength  of  field  is  attained,  even  when  the  current  flowing 
is  small  as  compared  with  the  maximum  current. 

This  is  equivalent  to  saying  that,  the  magnetization  given 
by  a  relatively  small  current  is  yet  sufficient  to  saturate  or 
nearly  saturate  the  iron  of  the  magnetic  circuit.  If,  however, 
the  field  be  kept  below  saturation  and  be  varied  in  strength, 
this  variation  may  be  used  to  accomplish  a  certain  degree  of 
speed  regulation.  Let  us  suppose  a  car  moving  on  a  level 
(or  on  a  uniform  grade),  and  at  such  a  speed  as  to  produce  a 
counter  E.  M.  F.  of  400,  the  applied  E.  M.  F.  being  500. 
For  convenience  assume  the  internal  resistance  of  the  arma- 
ture circuit  to  be  10  ohms.  Then  the  current  flowing  will  be 

lgg-400    =  ^ZI^:  =  L™  =  I0  amperes.     The  mechanical 
10  R  10 

work  done  would  be  400 X  10  =  ExC  =  4,000  watts. 

Now  suppose  it  is  desired  to  run  more  slowly.  Increase 
the  field  strength  by  10  per  cent.  The  counter  E.  M.  F.,  at 

5  oo  —  440 
the  same  speed,  would  be  440  volts,  the  current = 

6  amperes,  and  the  work  440  X  6  =  2 ,640  watts.  But  since  the 
car  requires  4,000  watts  to  maintain  the  previous  speed,  it  is 
evident  that  it  must  now  decrease  its  speed  until  there  shall 
be  an  equality  between  the  work  required  to  maintain  the 
lower  speed  and  the  work  done  by  the  motor  at  the  lower 
5 


66  THE    ELECTRIC    RAILWAY. 

speed  due  to  the  greater  field  strength.  Let  us  learn  what 
this  speed  is. 

It  was  seen  above  that  work  at  the  rate  of  4,000  watts  = 

4'000  =5.36  horse-power  =  176,880  foot-pounds  per  minute, 
746 

must  be  performed  in  order  to  maintain  the  speed  existing 
before  the  change  of  field  strength.  Suppose  the  car  to 
weigh  eight  tons,  and  suppose  that  on  the  particular  track  in 
question  a  horizontal  effort  of  25  pounds  per  ton  is  required 
to  overcome  all  resistances,  including  those  of  gears  or  other 
mechanism  between  the  armature  and  the  axles;  then,  a  total 
horizontal  effort  of  200  pounds  must  have  been  exerted.  This 
quantity,  multiplied  by  the  number  of  feet  traveled  per 
minute,  must  be  equal  to  the  number  176,880,  representing 
the  total  foot-pounds  of  energy  utilized  per  minute.  Hence, 

176,880 
the  travel  per  minute  = — =  884.4  feet  =  10.05  miles 

per  hour.     At  the  new  speed  we  must  have  a  similar  rela- 
tion- 
Work  done  in  foot-pounds 

— ^^ —  =  feet  traveled  per  minute ;  orr 

since  i  watt-minute  =  44.24  foot-pounds 

Work  in  watts 

7oo  —  44  24  =  ^eet  traveled  per  minute ;  whence,  the 

work  in  watts  =  4.52  X  feet  traveled  per  minute. 

The  number  of  watts  may  always  be  expressed  as  the 
product  of  the  counter  E.  M.  F.  by  the  current,  or  thus, 
watts  =  E'  C'. 

Let  Z'  =  strength  of  field  before  change.     Then, 
i.i   Z'=strength  of  field  after  change. 
Let  S'= speed  of  armature  before  change. 
S"=  speed  of  armature  after  change. 
C'  =  current  in  armature  before  change. 
C"= current  in  armature  after  change. 
'= counter  E.  M.  F.  before  change. 
E"=  counter  E.  M.  F.  after  change. 

X  S'.      (We  may  omit  the  number  of  armature 

urns.)     The  speed  of  armature  has  a  fixed  ratio  to  speed  of 

'  m  all  practice  of  to-day.     Hence,  we  may  now  assume 


MOTORS   AND    CAR    EQUIPMENT.  67 

some  convenient  ratio,  such  that;  for  example,  the  speed  of 
car  above  calculated,  i.e.,  884.4  feet  per  minute,  shall  cor- 
respond to  1,768.8  revolutions  per  minute  of  the  armature  (i 
revolution  =  0.5  of  a  foot  travel).  Then  we  may  write  E'  = 
Z'  X  i ,  768 . 8 .  Also  the  work  in  watts  =  4.52x0. 5  x  revolutions 
per  minute  =  2.26  S'. 

^=10=  SOP— Q, 768.8  Z'^    C,=  5QQ— LI  Z'S* 

10  10 

Z'X  1,768.8  =  400.      .\Z'  =  0.226. 

This  is  a  purely  relative  expression  for  the  strength  of  field, 
resulting  from  the  assumed  values  and  ratios  as  given  above. 
Then  i.i  Z'  =  Z"  =  0.2486. 

(i)   £"--=0.248  x  S", 
(2\  r"  =  SOP— (-248X8") 

10 

(3)   E"xC"=2.26xS". 
Placing  in  (3)  the  values   taken   from   (i)  and   (2),  we  have 

(4)  (0.248XS")X(-^0=^^)   =  2.26X8'; 

500  (0.248XS") 

—  =  Q.I  I. 
10 

.-.    (5)408.9  =  0.248x8".     .-.  S"=i,649. 

i  ,640 

Feet  per  minute  = =  824.5  =  9-4  miles  per  hour  ap- 
proximately. The  counter  E.  M.  F.  will  then  be  found  thus: 
E"=  0.248 X  1,649  =  408.9.  Also,  C"=  —  —  =  9.11, 

and  the  work  in  watts  =  408.9X9.11  =  3,725. 

In  like  manner,  if  the  field  be  weakened  10  per  cent.,  we 

(500 — 0.203  X  S"') 
may  find:  (0.203x8'")  X  -  -    =  2.26x8";  500 

—  .203x8"=  in.  .-.S'"=  389  -r-  .203  =  1,916.  Feet  per 
minute  =  958  =  10.9  miles  per  hour.  Counter  E.  M.  F.  =  3$9, 
current  =  n.i  amperes,  and  the  work  in  watts  =  389 X  1 1. 1 
*=  4,3i7- 

It  should  be  noted  that  these  results,  increase  of  speed  with 
decrease  of  magnetic  strength,  and  rice  rcrsa,  will  be  reversed 
if  the  changes  be  made  from  a  state  in  which  the  counter 
E.  M.  F.  is  less  than  one-half  the  initial  E.  M.  F.  When  the 


68  THE    ELECTRIC    RAILWAY. 

counter  E.  M.  F.  of  any  motor  is  just  one-half  the  initial 
E.  M.  F.,  the  rate  of  work,  that  is,  the  output  per  unit  of 
time,  is  greater  than  at  any  other  efficiency.  Since  this  output 
is  proportional  to  the  product  of  counter  E.  M.  F.  by  the  cur- 
rent, and  the  current  is  proportional  to  the  difference  between 
the  fixed  E.  M.  F.  of  the  line  and  the  counter  E.  M.  F.,  we 
have  the  output  varying  as  the  general  expression  E'x 
(E  _  E') ,  the  resistance  being  supposed  to  be  constant.  Now, 
the  product  of  a  number  as  expressed  by  E',  and  of  another 
number  which  is  equal  to  the  difference  between  the  first 
number  and  a  second  fixed  number,  will  always  be  a  maxi- 
mum when  the  first  number  is  just  half  the  second.  Suppose 
that  E  —  500,  for  all  values  of  E'. 

Take  E'=  249,  then  the  product  =  249X251  =  62,499; 

Take  E'=  250,  then  the  product  =  250X250  =  62,500; 

Take  E'  =  251,  then  the  product  =  251  X249  =  62,499; 
and  any  greater  departure  in  either  direction  from  250,  as 
the  value  for  E',  will  be  followed  by  a  further  departure 
from  the  maximum  value  for  the  product.  While  E'  is 
greater  than  the  difference  between  E  and  E'  (that  is,  when 
it  is  greater  than  one-half  E),  any  change  of  absolute  value 
made  in  E'  is  less,  proportionally,  than  the  corresponding 
change  in  the  smaller  quantity,  E  —  E'.  Thus  when  E',  as 
above,  was  taken  at  400,  and  the  magnetic  strength  was  in- 
creased, E7  also  increased  to  409,  a  change  of  2  per  cent., 
tending  to  increase  the  product  E'  C',  measuring  the  output. 
But  this  change  of  9  volts  was  necessarily  followed  by  an 
equal  change  in  the  difference  E — E',  reducing  it  from  100  to 
91,  a  reduction  of  9  per  cent.,  and  as  the  current  flowing  is 
directly  determined  by  the  quantity  E  —  E',  its  value  must  also 
change  by  9  per  cent.  Since,  therefore,  we  have  increased 
one  factor,  E',  by  2  per  cent.,  and  decreased  the  other,  C', 
by  9  per  cent.,  the  product  representing  the  new  output  must 
be  less  than  the  former.  But  if  the  original  value  of  E'  were 
200,  instead  of  400,  then  the  difference  E  — E'  must  be  300, 
and  any  addition  to  E'  resulting  from  an  increase  of  field 
strength  would  increase  this  factor,  E',  in  greater  propor- 
tion than  it  could  decrease  the  other  factor,  which  depends 
on  the  larger  number,  300.  The  net  result  would  therefore 


MOTORS   AND    CAR    EQUIPMENT.  69 

be  an  increase  in  the  product  E"  C",  and  the  car  would  con- 
sequently run  faster. 

The  fact  that  the  rate  of  work  of  a  motor  is  a  maximum 
when  its  efficiency  is  50  per  cent,  is  an  important  one.  A 
motor  which  has  been  properly  rated  as  a  1 5  horse-power 
machine  should  do  that  work  at,  say,  90  per  cent,  efficiency, 
since  that  is  an  easily  attainable  figure.  It  then  receives 
about  1 7  horse-power  of  electric  energy  to  perform  1 5  horse- 
power of  mechanical  work.  It  is  possible  to  obtain  a  rate  of 
20  horse-power  from  such  a  machine,  but  only  by  lowering 
its  efficiency,  say  to  60  per  cent.,  in  which  case  about  33 
horse-power  of  electric  energy  must  be  supplied  for  the 
20  horse-power  of  work. 

Having  discussed  the  relation  between  changes  of  field 
strength  and  of  speed,  we  now  pass  to  changes  of  load  and 
field  strength.  It  is  evident  that  if  in  the  case  above  assumed 
the  weight  of  the  car  or  condition  of  track  or  steepness  of 
grade  be  changed,  then  the  horizontal  effort,  200  pounds, 
required  to  maintain  uniform  motion,  will  also  change.  Let 
us  suppose  it  to  be  increased.  Then  if  nothing  be  done  to 
change  the  magnetic  strength  of  field,  or  the  impressed 
E.  M.  F.,  there  must  be,  in  a  series-wound  motor,  a  decrease 
of  speed,  and  that  whether  the  original  efficiency  be  above  or 
below  50  per  cent.  In  the  former  case,  increase  of  output 
(due  to  the  lowering  of  the  speed,  and  hence  of  the  counter 
E.  M.  F.)  will  meet  the  larger  demand,  which  is  itself  less 
than  if  the  speed  were  maintained  at  the  previous  rate,  and 
an  equilibrium  will  again  be  established,  when  E"  C"  =  Kx 
revolutions  per  minute. 

In  this,  K  is  constant,  corresponding  to  2.26  in  the  pre- 
vious calculations,  and  depending  on  the  particular  value 
of  the  horizontal  effort  required.  If,  before  change  of  load, 
the  motor  be  working  at  less  than  50  per  cent,  efficiency,  the 
decrease  of  speed  must  be  greater,  since  the  equality  between 
supply  of  and  demand  for  power  can  be  re-established  only 
because  the  one  decreases  less  rapidly  than  the  other.  Thus, 
the  supply,  varying  with  the  product,  E'  C',  will  tend  to 
decrease  with  decrease  of  E',  which,  in  a  constant  field,  will 
vary  directly  as  the  speed;  but  decrease  of  E'  means  increase 


jr0  THE    ELECTRIC    RAILWAY. 

of  C',  though  this  increase  will  be  less  proportionally  than 
the  decrease  of  E',  as  was  explained  above  when  considering 
field  strength.  The  product  of  these  two  factors  will  then 
evidently  diminish  less  rapidly  than  in  the  direct  ratio  to  the 
speed.  The  demand  for  power  will,  on  the  other  hand, 
decrease  in  exact  ratio  to  the  speed,  since  we  have  supposed 
the  horizontal  effort,  after  the  first  change  considered,  to 
remain  constant.  Another  change  would  produce  another 
lowering  of  speed,  another  adjustment  between  supply  and 
demand ;  and  this  process  may  continue  until  the  horizontal 
effort  becomes  greater  than  the  rolling  friction  between  wheel 
and  rail,  in  which  case  the  wheels  will  "skid;"  or  greater 
than  the  motor  with  maximum  current  in  the  armature  and 
fields  is  capable  of  overcoming,  in  which  case  no  motion 
whatever  will  be  produced. 

If  we  suppose  these  changes  of  load  to  take  place  when  the 
field  is  not  saturated,  we  may,  of  course,  use  the  changes  of 
field  to  counteract,  if  so  desired,  this  speed  reduction  which 
would  otherwise  follow.  Diminution  of  field  strength  would 
tend  to  increase  or  decrease  the  speed,  as  the  efficiency  is 
greater  or  less  than  50  per  cent. 

The  second  important  method  of  regulating  speed  under 
varying  loads  is  found  in  the  variation  of  the  E.  M.  F. 
applied  to  the  armature.  From  what  has  been  said  concern- 
ing the  measure  of  work  done,  it  will  be  readily  seen  that, 
other  things  being  equal,  decrease  of  applied  E.  M.  F.  must 
be  followed  by  decrease  of  output,  and  increase  of  E.  M.  F. 
by  increase  of  output.  Let  us  again  consider  the  case  of  a 
motor  developing  400  volts  counter  E.  M.  F.,  the  applied 
E.  M.  F.  being  500  volts,  the  current  being  10  amperes,  and 
the  resistance  to  motion  being  uniform.  If  now  we  reduce 
the  applied  E.  M.  F.  (E)  to  450  volts,  and  if  we  conceive 
that  for  a  moment  the  counter  E.  M.  F.  (E')  remains  at  400, 

the  current  would  be  reduced  to  5  amperes  thus :  45°~ 4—  =  s 

10 

Such  a  change  would  reduce  the  output  to  one-half  its  former 

value.     The  speed  would  then  necessarily  drop  to  one-half, 

unless  this  decrease  of  output  be  checked  in  some  way.     This 

k  would  come  through  the  fact  that  a  decrease  in  speed 


MOTORS   AND    CAR   EQUIPMENT.  7  1 

would  be  followed  by  a  corresponding  decrease  of  E',  which 
would  at  once  increase  C'.  To  learn  what  the  change  in 
speed  would  actually  be,  let  us  proceed  as  before. 

Using  the  new  value  for  E,  and  assuming  other  condition* 
as  before,  we  may  write 


or         E'x(45o  —  E')  =  22.6x8. 

We  suppose  now  that  the  field  will  remain  constant.  There 
will  then  be  a  very  simple  relation  between  E'  and  S,  that  is, 
they  will  vary  directly  each  with  the  other.  It  was  proved 
above,  under  the  conditions  assumed,  that 

S  =  4.42  E'.     Substituting  above,  we  have 

£'(450  —  E')  =  22.6X4-42E', 
or         450  —  £'=22.6x4.42.      .•.  £'=350.11. 
Calling  this  for  convenience  £'=350,  we  have, 

C'  =  —  '-      -  =  10  amperes,  as  before. 

Output  =  350X10=3,500  watts.  Speed  of  car,  in  feet  per 
minute  =—  —  =  774  =  8.8  miles  per  hour. 

The  original  speed,  it  will  be  remembered,  was  10.05  miles 
per  hour.  Now,  let  us  suppose  a  much  greater  change  in 
applied  E.  M.  F.,  say  to  250  volts.  Then 

250  —  E'=  22.6x4-42  =  99.9.      .'.  E'=  150. 

250  _  1  50 

C'=  -    -  =  10  amperes,  as  before. 
10 

Output  =  I50X  10  =1,500  watts. 

Speed  of  car  =  —    —  =  332  feet  per  minute  =3.8  miles 
4.52 

per  hour. 

Again,  suppose  E  =  200  volts,  then 

200  —  E'=ioo  (taken  for  99.9).      .-.  E'=  100  volts. 

200  —  100 
C  =  —  —  =  10  amperes,  as  before. 


Output  =  ioox  10  =  i  ,000  watts. 
Speed =—  —  =22 1  feet  per  mint 
Generally,  we  see  that  E'  =  E  —  100  =E  —  C'R.     R  is  a  con- 


Speed  =  —  —  =  2  2 1  feet  per  minute  =  2.5  miles  per  hour. 


-,  THE   ELECTRIC    RAILWAY. 

stant  by  the  construction  of  the  machine  (usually),  and  C', 
under  a  constant  load,  also  remains  constant,  while  E  varies, 
as  seen  above.  The  output  =  E'  C'=  (E  —  C'  R)  C'  will  then 
vary  in  proportion  to  the  difference  (E  —  C'  R) :  and  this  will 
vary  the  more  rapidly  as  E  approaches  the  constant  value  C' 
R.  Thus,  in  dropping  from  500  to  450,  the  change  of  50 
volts  is  applied  to  an  original  value  of  (E — C'  R)=45O — 
that  is,  a  change  of  one-eighth.  But  in  dropping  from  250 
to  200,  the  difference  of  50  volts  is  applied  to  an  original 
value  of  (E— C'  R)=  (250  —  ioo)=  150— that  is,  a  change  of 
one-third.  Looking  again  at  the  expression  E  —  C'  R  =  E  — 
100,  we  see  that  if  E  drops  to  100  volts,  the  output  will  be 

zero that  is,  the  car  will  not  move,  unless  the  resistance  to 

motion  be  in  some  way  diminished. 

We  may  say  then,  generally,  that  in  any  motor,  the 
strength  of  field  being  fixed,  a  certain  current,  C,  is  required 
to  produce  a  certain  torsional  effect  in  the  armature  (or  a 
certain  corresponding  horizontal  effort  through  the  car  axle). 
To  produce  this  current  over  the  internal  resistance  of  the 
motor,  R,  a  certain  E.  M.  F.  measured  by  C  R  is  required. 
If  the  impressed  E.  M.  F.  be  just  equal  to  C  R,  then  the 
rotating  force  in  the  armature  and  the  resistance  to  rotation 
will  just  counterbalance  each  other,  and  there  will  be  no 
motion.  Excess  of  pressure  over  that  measured  by  C  R  will 
produce  motion,  and  in  the  ratio  of  this  excess.  The  in- 
ternal resistance  will  cover  that  of  the  armature  and  field 
windings,  in  case  of  a  series  motor,  but  only  that  of  the 
armature  in  the  case  of  a  shunt  motor.  During  changes  of 
impressed  E.  M.  F.  the  constancy  of  field  strength  supposed 
above  will  follow  in  the  case  of  a  series  motor,  if  the  number 
of  turns  and  resistance  of  the  field  windings  remain  constant 
(since  we  have  seen  that  C  will  then  be  constant) . 

Having  seen  the  effects  produced  by  changes  in  field 
strength  and  in  impressed  E.  M.  F.,  we  should  now  con- 
sider the  convenient  and  customary  methods  of  producing 
those  changes. 

Suppose  three  coils  of  wire  to  be  wound  around  the  mag- 
net cores  of  a  motor,  as  shown  in  Fig.  3  5 .  Let  the  resistance  of 
each  be  one  ohm.  Connect  D  to  B  and  E  to  C.  Suppose  a 


MOTORS  AND  CAR  EQUIPMENT. 


73 


difference  of  potential  of  100  volts  be  maintained  between 
the  terminals  A  and  F,  then  the  total  resistance  of  this  field 
circuit  would  be  three  ohms,  the  three  coils  being  arranged 

in  series.     The  current  flowing  would  be =33.3  amperes. 

The  number  of  turns  would  be  two  for  each  coil  (one  above, 
one  below)  or  six  altogether.  The  magnetizing  effect  would 
be  measured  by  CxT  =33.3x6  =199.8. 

Now  suppose  the  connections  be  changed  by  disconnecting 
D  and  B,  E  and  C,  and  connecting  A,  B,  and  C  together,  and 
D,  E,  and  F  together.  The  resistance  of  the  three  coils,  now 
in  multiple,  will  be  only  one-third  of  an  ohm,  or  one-ninth 


F  c 


FIG.  35.— CONNECTIONS  FOR  COMMUTATING  FIELD  COILS. 

the  former  value.  The  current  will  be  nine  times  its  value, 
or  299.7.  The  number  of  turns  which  this  whole  current 
makes  around  the  magnet  is  only  two,  one  above  and  one 
below,  or  one-third  the  former  number.  The  magnetizing 
effect  will  be  measured  by  299.7x2  =  599.4,  or  three  times 
the  former  value.  If  the  magneto-motive  force,  199.8,  were 
itself  sufficient  to  saturate  the  magnets,  then  the  increase  to 
599.4  would  be  useless,  so  far  as  the  strength  of  field  is  con- 
cerned. But  if  a  force  of  say  2,000  ampere  turns  be  required 
for  saturation,  then  increase  from  199.8  to  599.4  will  t>e  fol- 
lowed by  a  proportional  increase  in  the  field  strength.  In 
either  case,  the  drop  of  potential  required  to  force  a  given 
current  over  the  field  windings  will  be  much  less,  with  the 
?econd  arrangement  of  coils,  in  which  the  resistance  is  rela- 


74  THE    ELECTRIC    RAILWAY. 

lively  low,  than  with  the  first  arrangement,  in  which  it  is 
relatively  high.  If,  therefore,  these  coils  be  placed  in  series 
with  the  armature,  we  have  a  ready  means  of  varying  the  E. 
M.  F.  applied  to  the  armature  itself,  and  also  of  varying  the 
magneto-motive  force  applied  to  the  field.  The  method  of 
regulation  thus  afforded  is  usually  known  as  that  by  "  com- 
mutation of  field  circuits." 

In  its  practical  application,  provision  has  been  made  for 
other  arrangements,  intermediate  in  effect  between  the  two 
above  described.  Thus,  (i)  starting  with  the  three  coils  in 
series,  (2)  one  may  be  cutout  or  short-circuited,  the  other 
two  remaining  in  series;  (3)  two  may  be  placed  in  multiple 
with  respect  to  each  other,  the  third  being  in  series  with  this 
multiple  combination ;  (4)  the  third  may  then  be  cut  out  or 
short-circuited,  leaving  only  the  two  in  multiple;  (5)  the 
arrangement  of  least  resistance  is  of  course  that  in  which  all 
the  coils  are  in  multiple.  If  through  any  suitable  switch  the 
various  combinations  be  effected  in  the  order  above  men- 
tioned, the  resistance  of  the  field  windings  becomes  less  at 
each  successive  step.  Suppose  a  car  moving  at  a  constant 
speed,  the  coils  being  in  arrangement  No.  i,  and  the  current 
required  being  great  enough  to  saturate  the  fields,  even  if 
the  number  of  turns  were  only  one-third  the  number  given 
by  this  arrangement.  If  wre  now  pass  through  No.  2,  No.  3, 
etc.,  successively,  and  there  be  no  change  of  load,  then  the 
E.  M.  F.  applied  to  the  armature  wrill  increase,  the  speed  will 
correspondingly  increase  (as  explained  above) ;  the  current 
will  remain  constant,  for,  by  supposition,  the  field  is  contin- 
uously saturated.  The  changes,  then,  do  not  affect  it,  and 
affect  the  armature  simply  by  varying  the  applied  E.  M.  F., 
as  would  be  the  case  if  the  field  circuits  were  independent,  as 
in  a  shunt  motor,  and  some  resistance  external  to  the  motor 
were  used  to  vary  the  drop  of  potential  on  the  lines  connect- 
ing the  dynamo  and  motor.  The  increase  of  output  without 
increase  of  current  is  due  to  a  progression  in  motor  efficiency. 
In  the  first  arrangement  the  resistance  of  the  field  circuit 
(hence  the  waste  of  energy  therein)  is  greater  than  would 
be  permissible  in  good  design,  were  it  not  plainly  set  forth 
as  a  means  of  regulation.  Only  in  the  last  arrangement  does 


MOTORS   AND    CAR    EQUIPMENT.  75 

the  resistance  become  as  low  as  good  design  would  give  were 
efficiency  alone  in  question. 

If  the  current  flowing  before  the  changes  be  less  than  that 
required  for  saturation  with  any  number  of  'turns  less  than 
that  given  by  the  first  arrangement,  then  the  increase  of 
speed  in  motors  in  practice  will  be  more  rapid  than  in  the 
case  just  considered,  and  the  current  will  not  remain  con- 
stant, but  will  increase.  For  there  are  now  two  causes  tend- 
ing to  increase  the  speed:  first,  the  increase  of  applied 
E.  M.  F.,  as  before;  second,  there  is  decrease  of  the  field 
strength,  due  to  the  decrease  of  turns,  which  tends  to  in- 
crease the  speed  (provided  the  efficiency  of  operation  be 
greater  than  50  per  cent.). 

As  explained,  the  increase  of  speed  due  to  this  cause 
requires  an  increase  of  current.  These  changes  tend,  indeed, 
to  check  each  other.  Thus,  increase  of  current  tends  to 
diminish  the  E.  M.  F.  applied  to  the  armature,  just  increased 
by  lowering  resistance,  and  to  strengthen  the  field,  just 
weakened  by  decrease  of  turns.  To  determine  the  constant 
speed  and  current  which  would  be  established  with  arrange- 
ment No.  2  or  No.  3,  etc.,  it  would  be  necessary  to  know  the 
relation  between  the  number  of  turns  and  the  resistance  of 
the  three  coils.  Assuming  them  to  be  equal  in  all  respects, 
the  changes  of  turns  and  the  resistances  may  be  seen  from 
the  following  table : 

ARRANGEMENT.  TURNS.  RESISTANCE. 

1  6  3 

2  4  2 

3  4  i-5 

4  2  0.5 

5  2  0.3 

In  moving  from  step  to  step,  the  rate  of  change  is  evidently 
not  uniform,  but  is  continuous  in  the  direction  of  higher 
speed.  By  making  the  coils  unequal,  it  is  possible  more 
equally  to  divide  the  total  change  effected  from  first  to  fifth, 
but  in  the  very  limited  space  usually  available  for  windings, 
such  inequality  may  require  dangerously  small  cross-section 
for  the  maximum  currents  required. 

In  the  early  motors  of  the  Sprague  Electric  Railway  and 
Motor  Company,  rated  at  7.5  horse-power,  at  ordinary  street- 


THE    ELECTRIC    RAILWAY. 


car  speeds,  say  ten  miles  per  hour,  and  for  soo-volt  circuits, 
the  turns  and  resistances  were  as  follows : 


Positions  2  and  3,  and  5  and  6,  are  effectively 

Switch  No...      i     ;2and3  ^4_^and_^;_7_  !  the  same. 

^T".!  I         !.      ;       ,        i  3      .Proportional  numbers,  not  absolute  values. 

Armature  R  =  1.4,  constant. 

Res  !  20  o  '      12      i  9.5  \      5-0    i  3.2  (Actual  R  in  ohms,  including  armature. 

In  a  later  machine,  rated  at  15  horse-power,  under  the 
same  conditions  the  field  resistance  of  each  motor  was  8.42 
ohms,  total,  made  up  of  three  coils  of  2.16,  2.65,  and  3.61 
ohms,  respectively,  the  number  of  turns  being  as  11.5,  n, 
and  15,  respectively. 

In  using  this  method,  the  principal  difficulty  has  been  met 
in  disposing  of  the  excessive  heat  necessarily  generated  in 
the  compact  mass  of  field  windings.  Many  ordinary  forms 
of  insulation  have  been  found  to  deteriorate  under  the  influ- 
ence of  the  high  temperatures  maintained.  When,  however, 
the  incidental  difficulties  have  been  met  by  use  of  proper 
material,  the  method  is  a  convenient  one  for  securing  a  con- 
siderable range  of  regulation.  The  mechanism  required, 
external  to  the  motor,  consists  only  of  such  a  switch  as  will 
in  a  simple  manner  produce  the  changes  of  connection,  such 
as  described  above.  In  the  practice  of  the  Edison  Electric 
Company  (successors  in  this  business  to  the  Sprague  Electric 
Railway  and  Motor  Company,  who  most  widely  introduced 
the  method  considered),  these  changes  of  connection  have 
been  produced  by  taking  all  the  coil  terminals  to  a  series  of 
spring  contacts,  pressing  against  metal  surfaces  arranged  on 
a  cylinder.  These  surfaces  are  so  shaped  that  rotation  of  the 
cylinder  produces  the  desired  combinations.  It  is  of  course 
possible  to  use  a  smaller  or  larger  number  of  independent 
coils  than  three.  In  the  former  case,  the  number  of  com- 
binations giving  different  effects  is  not  sufficient  for  a  smooth 
control.  In  the  latter,  the  complication  of  switches  becomes 
excessive. 

The  control  by  external  resistance,  thus  lowering  or  raising 
the  E.  M.  F.  applied  to  the  motor,  has  been  widely  used  and 
scarcely  needs  extended  description.  The  practical  problem 
has  been  to  secure  a  convenient  rheostat,  made  of  such 


MOTORS    AND    CAR    EQUIPMENT. 

material  as  will  give  the  high  electric  resistance  required, 
and  at  the  same  time  withstand  the  heat  produced.  Open 
coils  of  iron  or  German-silver  wire  seem  to  offer  the  most 
ready  means  of  attaining  the  end  in  view,  but  the  space 
demanded  is  found  excessive  as  compared  with  the  meagre 
dimensions  required  by  the  condition  that  the  whole  mech- 
anism shall  go  under  a  car  floor.  Plates  of  thin  iron,  bent 
into  a  "  U"  shape,  insulated  from  each  other  by  mica,  and 
arranged  in  a  semi-circular  frame,  have  composed  the  rheo- 
stats used  by  the  Thomson-Houston  Electric  Company,  which 
has  widely  used  this  method  of  control.  An  arm  moving 
around  the  center  of  the  semi-circular  frame  carries  contact 
pieces  over  the  convex  surface  of  the  resistance  plates,  leaving 
all,  a  part,  or  none  of  them  in  circuit,  according  as  a  low,  or 
higher,  or  maximum.  E.  M.  F.  is  desired  to  be  applied  to  the 
motor.  When  this  method  is  used,  the  field  winding  should 
be  permanently  of  low  resistance,  but  sufficient  to  nearly  satu- 
rate the  cores  at  all  loads. 

One  of  the  two  methods  of  control  thus  described,  or  a 
combination  of  them,  has  been  used  in  almost  every  effort 
at  electric-railway  work.  The  chief  exception  is  found  in 
storage-battery  cars,  in  which  the  batteries  themselves  may 
be  thrown  into  various  combinations,  thus  changing  the 
E.  M.  F.  applied  to  the  motors.  There  are  few  examples,  if 
any,  of  the  exclusive  use  of  either  method  for  motors  now 
being  manufactured.  Thus,  the  Edison  Company  uses  an 
external  resistance  to  prevent  too  great  a  rush  of  current  into 
the  motors  when  starting ;  their  proper  resistance,  even  with 
all  the  coils  in  series,  being  so  low  when  the  two  motors  are 
connected  in  multiple  on  a  5oo-volt  circuit  as  to  cause  a  cur- 
rent of  about  100  amperes  to  flow.  This  is  usually  much  in 
excess  of  that  actually  required  for  a  comfortable  start  of  the 
car,  and  is  of  course  highly  objectionable  in  respect  both  to 
its  effect  on  the  motor  and  its  demand  upon  the  station. 
This  "starting  coil,"  as  it  has  been  called,  is  cut  out  of  cir- 
cuit as  soon  as  the  start  has  been  made.  The  switch  then  pro- 
duces the  first  combination  of  field  coils,  as  above  described, 
and  as  it  rotates  further,  produces  the  others  successively — 
tnis  commutation  of  the  windings  being  the  chief  means  of 


7g  THE   ELECTRIC    RAILWAY. 

control.  On  the  other  hand,  the  Thomson-Houston  Electric 
Company,  which  has  used  the  external  rheostat  as  the 
chief  means  of  control,  in  the  last  position  of  the  switch, 
when  the  full  line  potential  has  been  applied  to  the  motors, 
short-circuits  or  cuts  out  one  of  the  two  parts  of  the  field 
winding.  Up  to  this  last  point  these  two  have  been  con- 
nected in  series,  acting,  indeed,  as  one  coil.  Now,  in  order  to 
increase  speed,  a  large  part  of  the  turns  are  made  ineffective, 
hence  the  field  is  weakened  and  the  increase  of  current  and 
increase  of  speed  take  place,  as  already  explained.  The  total 
resistance  of  the  rheostat  is  fixed  at  such  a  value  as  will  allow 
to  flow  the  maximum  current  required  for  starting  from  rest, 
the  line  potential  being  taken,  as  in  practice,  at  500  volts. 
This  total  resistance  may  then  be  so  subdivided  as  to  produce 
any  desired  rate  of  change. 

In  case  two  or  more  motors  be  used  on  one  car  or  train, 
there  remains  a  third  method  of  producing  a  considerable 
range  of  control;  namely,  by  changing  the  machines  from 
the  multiple  to  the  series  arrangement,  with  respect  to  each 
other,  and  vice  -ccrsa.  The  applied  E.  M.  F.  is  just  one-half 
in  the  second  case  what  it  is  in  the  first,  if  there  be  two 
motors,  one-third  if  there  be  three,  and  so  on.  A  variation 
of  this  method  might  be  had  by  changing  the  field  windings, 
leaving  the  armatures  permanently  in  series  or  permanently 
in  multiple.  The  series  arrangement  of  the  two  machines  is 
of  special  value  in  starting  a  car  and  in  maintaining  low 
speeds.  In  both  cases  it  may  become  the  equivalent  in  effect, 
and  the  superior,  in  economy,  of  either  of  the  above-described 
methods  of  control.  Through  this  method  it  is  indeed  pos- 
sible to  make  the  same  motors  fulfill  widely  different  service 
conditions.  Thus,  suppose  cars  are  to  begin  their  trips  in 
the  most  populous  portions  of  a  city,  where  many  stops  and 
relatively  slow  running  are  unavoidable,  while,  on  reaching 
the  suburbs,  long  runs  at  high  speeds  are  desired.  We  may 
then  design  motors  which,  if  placed  in  multiple  and  per- 
mitted to  run  at  say  2  5  miles  per  hour,  will  develop  each  2  5 
horse-power.  If  placed  in  series,  they  would  each  develop 
12.5  horse-power,  at  12.5  miles  per  hour,  and  at  both  speeds 
their  efficiency  may  be  high.  To  meet  speeds  lower  than  1 2 .5 


MOTORS   AND    CAR    EQUIPMENT.  79 

miles  per  hour,  the  load  being  such  as  would  permit  only 
that  speed  if  the  impressed  E.  M.  F.  be  250  volts  (half  of 
500  for  each),  we  may  resort  to  either  of  the  two  methods  of 
general  control,  the  motors  as  a  whole  being  kept  in  series. 
So,  for  speeds  between  12.5  and  25  miles  per  hour,  the  tor- 
sional  effect  required  being  still  the  same,  we  may  in  like 
manner  control  the  two  motors  placed  in  multiple.  In  case 
of  any  heavy  and  long  grade,  this  latter  arrangement  would 
be  used. 

Early  in  1888  multiple-series  switches  were  placed  by  the 
Sprague  Electric  Railway  and  Motor  Company  on  many  of 
the  cars  installed  by  it.  They  were  subsequently  abandoned, 
not  because  of  failure  to  produce  the  anticipated  results,  but 
because  at  that  date,  when  many  other  things  were  giving 
much  trouble,  it  seemed  wise  to  sacrifice  variety  of  effect  to 
simplicity  of  mechanism. 

Others,  when  studying  the  problem,  have  desired  to  make 
the  change  from  series  to  multiple  connection  a  step  in  the 
progression  constantly  taking  place  after  and  during  every 
stop  of  the  car,  and  hence,  to  be  produced  when  the  car  is  in 
motion  and  current  flowing.  This  may  involve  a  quick  jump 
of  the  car,  in  one  case,  or  a  corresponding  drag  in  the  other, 
both  occurrences  being  objectionable.  The  greatest  value 
of  the  method  seems  to  be  as  pointed  out  above,  in  which 
cases  the  breaking  of  the  circuit  and  operation  of  a  switch, 
separate  from  that  used  for  general  control,  would  be  per- 
missible though  shown  by  recent  experience  to  be  needless. 

Now  that  many  previously  troublesome  features  of  railway 
practice  have  been  made  easy,  while  at  the  same  time  there 
is  constant  increase  in  the  variety  of  service  called  for,  at- 
tention is  actively  devoted  to  this  method.  It  appears  in 
several  important  installations  recently  made,  and  its  use 
will  doubtless  become  more  general.  Its  advantages  are 
evident.  See. Appendix  F. 

More  than  nine-tenths  of  all  the  installations  thus  far  made 
have  shown  two  motors  on  a  car,  and  these  two  have  almost 
invariably  been  placed  in  multiple.  Each  is  therefore  wound 
so  that  it  may  produce  the  maximum  speed  required,  having 
between  its  terminals  the  full  line  potential.  If  they  are 


8o  THE    ELECTRIC    RAILWAY. 

placed  in  series,  there  is,  of  course,  no  harm  done,  the  effect 
being  only  to  produce  a  lower  speed  in  this  way  rather  than 
by  high-resistance  field  coils,  or  an  external  rheostat.  When 
the  motors  are  placed  in  multiple,  each  is  nearly  independent 
of  the  other.  One  may  have  its  circuit  broken  while  the 
other  is  propelling  the  car.* 

If,  on  the  other  hand,  the  motors  are  so  wound  as  to  give 
maximum  required  speed  when  placed  in  series  across  the 
line,  and  this  be  considered  the  normal  relation,  it  then  be- 
comes practically  impossible  to  place  them  in  multiple.  If 
one  machine  must,  by  reason  of  injury,  be  cut  out,  then  the 
other  must  be  protected  by  some  external  resistance,  or  left, 
at  best,  to  run  with  a  high-resistance  field.  The  advantage 
to  be  gained  lies  in  this,  that  for  a  given  quality  of  work- 
manship there  will  be  fewer  failures  of  insulation,  since  the 
pressure  on  each  motor  is  only  half  that  due  to  the  line  poten- 
tial. Further,  this  prevents  effectively,  save  in  a  special 
case,  that  widely  unequal  division  of  labor  which  has  often 
been  observed  between  two  motors  on  the  same  car.  This 
is  generally  due  to  a  difference  of  resistance  in  the  two  mag- 
netic circuits. 

Its  effect  can  be  best  understood  by  considering  the  fact 
that  the  current  flowing  over  an  armature  is  due  to  the  differ- 
ence between  impressed  E.  M.  F.  and  counter  or  self-induced 
E.  M.  F.  The  speed  of  the  two  armatures  must,  in  car  ser- 
vice, be  practically  equal.  The  number  of  turns,  save  by 
gross  carelessness  in  manufacture,  will  also  be  equal.  Now 
suppose  that  by  reason  of  either  or  both  of  the  causes  men- 
tioned, the  two  armatures  are  moving  in  fields  of  force  dif- 
fering in  strength  by  5  per  cent,  of  the  stronger,  the  number 
of  amperes  being  the  same.  Consider  armature  (A)  as  gen- 
erating a  counter  E.  M.  F.  490.  Then  armature  (B)  would 
generate  490— (490  X  0.05)=  465.5.  The  effective  E.  M.  F. 
would  then  be  10  volts  for  (A)  and  34.5  for  (B)— the  line  E. 
M.  F.  being  as  usual  taken  at  500  volts.  The  current  would 

*  A  trouble  that  has  sometimes  occurred  with  alarming  frequency,  however,  consists  in 
this:  that  the  commutator  of  one  motor  begins  to  "throw  solder" — i.e.,  melts  the  solder 
at  the  connections  with  armature  wires.  In  such  case,  look  for  a  loose  connection  in  the 
other  motor.  Such  a  loose  connection,  being  of  high  resistance,  may  have  thrown  an  un- 
due load  on  the  motor  which  has  shown  the  trouble  at  commutator,  this  load  causing  an 
excess  of  current  resulting  in  the  melting  of  the  solder. 


MOTORS   AND    CAR    EQUIPMENT. 


81 


be  -~-  for  A  and  -^-  for  B,  or,  since  the  resistances  of  the 

armatures  are  practically  equal,  we  have  for  a  5  per  cent, 
difference  in  the  field  strength  a  difference  in  the  current  of 
345  per  cent.  This  supposes  the  currents  in  the  fields  of  the 
two  machines  to  be  identical,  and,  indeed,  such  has  generally 
been  the  case,  the  connections  of  the  two  machines,  however 
controlled,  having  been  usually  as  shown  by  Fig.  36,  the  effect 
mentioned  not  having  been  fully  appreciated  until  lately. 

The  field  windings  being  simply  so  many  turns  of  wire 
having  equal  resistance  in  the  two  motors,  the  division  of 


FIG.  36.  FIG.  37. 

METHODS  OF  CONNECTING  MOTORS  IN  PARALLEL. 

current  from  A  to  B  will  be  equal,  while  from  B  to  C  the 
division  will  be  determined  by  strength  of  field,  as  just 
explained. 

If  the  connections  are  as  shown  in  Fig.  37  the  possible  dif- 
ferences are  very  largely  reduced. 

In  this  case,  each  field  winding  with  its  armature  consti- 
tutes a  separate  circuit,  and  the  excessive  current  which 
would  tend  to  flow  in  B,  under  the  condition  of  unequal 
reluctance  of  field,  will  be  checked  by  its  own  effect  in 
increasing  the  ampere  turns  in  circuit  B  over  that  in  circuit  A, 
thus  increasing  the  counter  E.  M.  F.  The  current  in  B  will, 


32  THE    ELECTRIC    RAILWAY. 

unless  saturation  for  both  machines  has  been  reached,  be 
greater  than  that  in  A,  since  by  supposition  the  field  strength 
is  less  for  a  given  current  in  B  than  in  A,  and  the  counter 
E.  M.  F.  must  then  be  less.  But  the  difference  will  be  only 
proportional  to  the  difference  of  permeability  below  saturation. 
The  connections  as  shown  in  Fig.  36,  in  which  the  machines 
are  cross-connected,  have  the  advantage  of  offering  greater 
facility  for  reversing  the  current.  Thus,  one  switch,  revers- 
ing the  current  over  both  fields  or  both  armatures,  through 
the  terminals  A  and  B.  or  B  and  C,  controls  both  motors. 
If  the  machines  be  not  cross-connected,  then  a  separate 
switch  must  be  used  for  each  machine.  This,  however,  is  a 
matter  of  small  consideration  compared  to  the  importance  of 
the  result  secured  by  it.  The  connection  of  the  two  motors 
in  series  of  course  renders  unnecessary  the  double  reversing" 
switch,  and  makes  the  current  in  the  two  motors  identical. 
Another  method  of  meeting  this  particular  difficulty  was 
used,  indeed,  is  still  used,  on  some  of  the  cars  equipped  by 
the  Edison  Company. 

In  this  method,  the  two  motors  remain  in  multiple:  a  coil 
is  placed  around  the  field  of  motor  (A')  and  in  series  with  the 
armature  of  motor  (B) :  likewise  on  B,  a  field  coil  is  in  series 
with  armature  (A).     The  machines  remained  cross-connected 
as  shown  above. 

These  additional  coils  were  known  as  "balancing  coils." 
If,  due  to  its  relatively  weak  field,  armature  (B)  tends 
to  take  more  current  than  its  companion,  this  current  tra- 
versing the  coils  around  the  magnets  of  A,  and  in  a  direction 
opposite  to  that  of  the  principal  windings  of  A,  diminishes 
the  field  strength  of  that  machine.  Likewise,  the  current 
m  armature  A  circulates  around  B  and  diminishes  its  field 
strength,  but  by  a  less  quantity  than  that  subtracted  from  A. 
The  tendency,  then,  is  plainly  toward  equality.  The  method 
has  been  applied  with  considerable  but  varying  success. 
Thus,  suppose  one  machine,  A,  to  be  over-saturated;  the 
other,  B,  to  be  below  saturation.  Its  armature  current, 
though  greater  than  that  of  A,  may  have  a  less  effect 
in  demagnetizing  A  than  will  the  current  of  A  have  in  de- 
magnetizing B,  and  the  inequality  would  thus  be  increased. 


MOTORS   AND    CAR    EQUIPMENT.  83 

This  may  be  taken  to  be  an  exaggerated  case,  but  yet  it  is 
possible ;  and  since  it  shows  an  actual  reversal  of  the  intended 
effect,  it  is  plain  that  in  cases  of  smaller  and  more  probable 
differences,  the  device  may  at  least  vary  widely  in  its  effect 
without  actual  reversal. 

If,  further,  each  pair  of  machines  before  being  mounted 
were  carefully  studied,  the  adjustment  might  certainly  be 
made  very  accurate.  The  practical  necessities  of  manufacture 
and  installation  prevent  this.  The  chief  objection  to  this 
method  may  be  stated  in  this:  that  while  it  introduces  a 
complication  of  wiring  equal  to  or  greater  than  that  demanded 
by  the  double  reversing  switch,  it  does  not  cure  the  evil  so 
efficaciously  or  so  simply  as  by  independence  of  circuit  and 
double  reversing  switch,  or  by  placing  the  motors  in  series. 

This  unequal  division  of  current  becomes  an  evil  only 
when  occurring  under  heavy  loads,  such  that  one  machine 
may  be  required  to  do  much  more  than  its  normal  work,  in 
which  case  the  efficiency  of  its  performance  may  be  consider- 
ably lowered ;  or  the  over-load  may  go  so  far  as  to  injure  the 
insulation  by  excessive  heat. 

Before  leaving  the  subject  of  speed  control,  it  should  be 
stated  that  numerous  designs  have  been  made  (and  a  few 
executed)  looking  to  continuous  and  approximately  constant 
speed  of  armature,  mechanical  devices  being  used  to  effect  a 
varying  speed  reduction  between  the  armature  and  the  axle. 
In  some  cases,  usually  by  the  use  of  friction  plates  or 
hydraulic  gearing,  the  change  of  ratio  between  the  armature 
and  the  axle  speed  is  effected  by  some  continuous  movement, 
carrying  the  ratio  by  changes  of  insensible  value  from  unity 
to  infinity  or  the  reverse. 

In  other  cases,  usually  by  the  use  of  some  form  of  the  so- 
called  sun-and-planet  or  external  and  internal  gearing,  the 
changes  are  abrupt  and  limited  in  number.  This  variation 
of  leverage,  however  obtained,  is  certainly  in  itself  an  incon- 
testable advantage.  By  means  of  it  an  armature  of  minimum 
weight  and  working  at  a  maximum  efficiency  may  be  made 
to  serve  for  a  given  range  of  work. 

If  used  in  connection  with  a  shunt  field,  the  armature 
speed  might  be  as  constant  as  in  the  case  of  stationary  motors 


g4  THE   ELECTRIC   RAILWAY. 

doing  variable  work.  Change  of  work  requirement  would  be 
followed  by  change  of  current  consumption,  which  would 
correspond  to  slight  changes  of  field  strength,  the  motor 
efficiency  and  the  speed  of  armature  remaining  nearly  con- 
stant. The  proper  determination  of  relations  in  such  case 
would  be  as  follows:  First  consider  the  maximum  allowable 
speed  of  armature,  as  determined  by  electrical  and  mechanical 
effects  in  the  armature,  and  its  directly  attached  devices. 
Calculate  the  maximum  output  that  might  be  required  for 
such  a  length  of  time  as  would  cause  the  efficiency  of  the  motor 
during  that  time  to  be  of  importance.  Assume  that  this 
output  should  be  at  an  efficiency  of,  say,  90  per  cent. 
The  current  required  then  becomes  known,  likewise  the 
resistance  of  the  armature  conductors.  Their  cross-section  re- 
sults from  making  proper  allowance  for  the  heating  effect  of 
such  a  current  over  such  a  resistance.  Their  length  is  deter- 
mined by  the  relation  between  the  cross-section  and  the 
resistance.  The  size  of  the  loop,  or  of  the  body  of  the  arma- 
ture, is  calculated  from  the  conditions  that  the  given  length 
of  conductor  rotating  in  a  field  of  assumed  strength,  say 
one-half  that  of  saturated  iron,  shall  generate  a  counter 
E.  M.  F.  of  the  required  magnitude.  The  other  dimensions 
of  the  motor  follow  from  ordinary  calculations. 

The  average  output,  and  those  below  the  average,  are  all 
obtained  at  high  efficiency,  the  field  strength  being  increased, 
the  counter  E.  M.  F.  being  slightly  increased,  and  the  cur- 
rent largely  decreased  thereby. 

In  case  series  motors  are  used  with  this  method,  it  would 
seem  best  so  to  wind  the  field  magnets  as  to  produce  satura- 
tion with  a  relatively  small  service  current.  The  armature 
would  then  for  the  most  part  rotate  in  a  constant  field ;  slight 
changes  of  the  speed  of  the  armature  would  be  followed  by 
considerable  changes  of  current,  corresponding  to  changes 
in  the  required  output,  practically  the  whole  speed  regulation 
being  effected  through  the  particular  mechanical  device  used. 
Should  the  field  strength  become  constant  only  at  relatively 
large  currents,  there  would  be  a  considerable  variation  of  the 
armature  speed,  which  might  or  might  not  be  in  the  same 
direction  as  that  desired  to  be  effected. 


MOTORS   AND    CAR   EQUIPMENT.  85 

Summarizing  concerning  this  general  method,  it  may  be 
said  that  if  variable  gearing  could  be  had,  in  which  the  com- 
plications would  be  insignificant,  while  its  reliability  and 
efficiency  of  transmission  would  be  great,  then  its  use  would 
become  general.  Active  minds  are  at  work  on  the  problem, 
and  it  may  soon  be  solved.  Meanwhile,  the  controlling  de- 
mand for  simplicity  excludes  the  devices  thus  far  presented. 

The  action  of  shunt  motors  has  just  been  compared  to  that 
of  series  motors  in  the  particular  case  of  mechanical  regula- 
tion of  speed.  It  remains  to  inquire  why  they  have  not  been 
used  in  the  already  extensive  application  of  electric  motors 
to  traction  work.  At  the  outset  it  may  be  stated  that  the 
particular  quality  named  by  Silvanus  P.  Thompson  as  advan- 
tageous to  the  series  motor,  in  comparison  with  the  shunt 
machine,  is  in  fact  of  no  practical  value.  On  p.  539  of  his 
great  work,  "Dynamo  Electric  Machinery,"  Thompson  says: 

"  The  fact  that  the  torque  of  a  series  motor  depends  only 
on  the  current,  is  of  advantage  in  the  application  of  motors 
to  propulsion  of  vehicles  (such  as  tram-cars)  which  at  start- 
ing require  for  a  few  seconds  a  power  greatly  in  excess  of 
that  needed  when  running.  To  start,  a  large  current  must 
be  turned  on.  One  convenient  way  of  arranging  this  is  to 
use  two  motors,  coupled  habitually  in  series.  When  start- 
ing, they  are,  by  moving  a  commutator,  coupled  in  parallel. 
This  doubles  the  electromotive  force  for  each,  and  at  the 
same  time  halves  the  resistance.  For  a  few  seconds  a  very 
strong  current  flows — much  stronger  than  that  which  the 
motors  would  stand  for  any  prolonged  work — and  so  pro- 
vides the  needful  additional  torque." 

As  has  been  pointed  out  above,  the  practical  difficulty 
met  with  in  electric-railway  design  is  to  get  sufficiently  high, 
not  sufficiently  low,  initial  resistance.  The  normal  resist- 
ance, even  of  two  series  motors,  placed  in  series  with  each 
other,  is  not  high  enough  to  prevent  needlessly  large  starting 
currents  from  flowing.  The  absence  of  opportunity  for  any 
considerable  experience  in  this  direction  offers  ready  ex- 
planation for  so  slight  an  error  in  what  is,  perhaps,  the  most 
satisfactory  all-round  practical  electrical  treatise  in  the  Eng- 
lish language. 


86  THE    ELECTRIC    RAILWAY. 

A  disadvantage  which  was  early  discovered  in  the  use  of 
shunt  motors  is  stated  thus  by  Kapp  ("  Electric  Transmission 
of  Energy,"  pp.  316,  317),  speaking  of  the  little  Blackpool 
electric  tramway :  "  It  has  been  explained  that  the  speed 
of  a  shunt  motor,  whei  running  light,  can  never  exceed  a 
certain  limit;  whereas  a  series  motor  may,  under  the, same 
conditions,  assume  a  dangerously  high  speed.  On  purely 
theoretical  grounds  shunt  motors  are,  therefore,  more  suitable 
for  tramway  work.  But  a  serious  practical  difficulty  was 
soon  encountered.  It  arose  from  the  uncertainty  of  elec- 
trical contact  between  the  wheels  and  the  rails.  When  a 
current  of  electricity  has  to  pass  through  two  pieces  of  metal 
in  contact,  the  first  condition  is  that  the  surfaces  should  be 
clean,  and  that  is  precisely  the  condition  which  cannot 
always  be  fulfilled  in  a  tramway  exposed  to  the  weather  and 
overrun  by  other  traffic.  It  would  thus  occasionally  happen 
that  the  current  was  interrupted  for  a  very  short  time,  per- 
haps only  a  fraction  of  a  second,  but  the  interval  was  suffi- 
cient to  cause  the  field  of  the  motor  to  lose  its  magnetism. 
The  consequence  of  this  was,  that  when  contact  was  restored 
and  the  current  began  again  to  flow,  the  armature  was  not 
able  to  offer  any  counter  electromotive  force,  and  an  abnor- 
mal rush  of  current  took  place  before  the  field  magnets  had 
had  time  to  again  become  excited.  It  will  be  noticed  that 
the  injurious  effect  here  described  will  be  the  greater,  the 
bwer  the  resistance  of  the  armature;  that  is  to  say,  the  more 
efficient  the  motor,  the  more  will  it  suffer  from  an  occasional 
interruption  of  current.  Since  it  was  impossible  to  abso- 
lutely avoid  these  interruptions,  the  use  of  shunt  motors  was 
discontinued,  and  series  motors  were  substituted.  In  a  series 
motor  the  intensity  of  the  field  and,  therefore,  the  counter 
electromotive  force  of  the  armature  are  at  once  restored 
when  the  current  begins  to  flow,  and  no  abnormal  rush  of 
current  can  take  place.  To  prevent  racing  when  lightly 
loaded,  variable  resistances,  placed  below  the  platform  at 
either  end  of  the  car,  have  to  be  used.  These  resistances 
are  also  employed  for  regulating  the  speed  when  the  motor 
is  doing  a  fair  amount  of  work." 

It  seems  that  this  difficulty  could  readily  be  overcome   by 


MOTORS   AND    CAR   EQUIPMENT.  8/ 

a  simple  automatic  device,  which  would  open  the  armature 
circuit  unless  the  field  circuit  is  closed.  Such  a  device  would 
doubtless  have  been  used,  were  there  any  marked  advantages 
in  other  respects  of  the  shunt  over  the  series  winding.  The 
reasons  for  the  use  of  the  latter  are :  i .  The  early  prejudice 
founded  upon  the  facts  related  by  Kapp.  2.  That  in  a  series 
motor  the  regulation  of  field  strength  and  applied  E.  M.  F. 
may  be  effected  through  one  mechanism,  the  current  in  the 
armature  and  the  field  coils  being  the  same.  3.  The  facility 
of  using  the  field  windings  as  a  rheostat,  as  explained  above. 

4.  The  fact  that  the  insulation  of  the  field  coils  is  somewhat 
easier   in    the   series    machine,    the    difference   of   potential 
between  the  terminals  being  much  less  than  in  the  shunt 
motor.      5.  The  fact  that  up  to  saturation  there  is  an  auto- 
matic field  regulation. 

These  reasons  are  good  and  sufficient  to  determine  present 
practice,  though  it  is  certainly  true  that  good  service  would 
"be  had  from  a  shunt-wound  motor,  speed  control  being 
effected  mechanically  or  through  rheostats  placed  in  the 
armature  and  the  field  circuits,  to  which  may  or  may  not  be 
added  commutation  of  field  windings. 

In  considering  the  motor,  in  place,  in  relation  to  the  other 
necessary  parts  of  the  car,  we  are  led  to  discuss : 

(A)  The  manner  of  connecting  the  armature  shaft  with 
the  axle. 

(B)  Convenience   of  position  with  respect   to  inspection, 
removal  and  repairs. 

The  means  used  for  transmitting  power  from  the  armature 
shaft  to  the  axle  have  been : 

i.  Spur  gears.  2.  Sprocket  chains.  3.  Beveled  gears.  4. 
Connecting  rods,  as  from  one  locomotive  driver  to  the  other. 

5.  Worm  gears.     6.  Ordinary  belting.     7.   Ropes  and  pul- 
leys.    8.  Friction  plates,  etc.,  as  explained,  for  variable  speed 
reduction.     9.  Centering  of  armature  directly  on  the  axle. 

i.  Spur  Gears. — Perhaps  99  per  cent,  of  all  the  rail- 
way motors  now  running  are  connected  by  spur  gearing. 
From  this  general  use,  it  follows  that  the  burden  of  proof 
lies  upon  any  other  method  before  it  may  be  considered  as 
being  practically  in  the  field.  The  efficiency  of  this  method 


38  THE    ELECTRIC    RAILWAY. 

may  be  roughly  stated  as  90  per  cent,  for  each  couple  of 
intermeshing  gears,  if  exposed  to  grit,  and  provided  the  load 
be  reasonably  large.  When  the  load  is  very  small,  the  ^xed 
loss  in  friction  causes  the  efficiency  to  be  low. 

If  the  gears  be  inclosed  in  oil-tight  cases,  as  is  now  largely 
practiced,  the  couple  efficiency  is  from  90  to  95  per  cent,  at 
medium  or  heavy  loads.  In  mechanical  simplicity  and  relia- 
bility, under  reasonably  good  design,  there  is  little  to  be 
desired.  The  serious  problems  that  have  been  met  are: 

(a)  Choice  of  material,  regard  being  had  to  strength,  free- 
dom from  noise,  and  cost.  Cast  iron  for  the  heaviest  gear 
(that  on  the  axle),  with  machine-cut  teeth,  has  been  almost 
exclusively  used.  For  the  smaller  gears,  running  at  higher 
speeds,  cast  iron,  steel,  brass,  bronze,  wood  (for  the  teeth), 
rawhide — all  have  been  tried,  with  a  gradual  settling  down 
to  steel  or  gun-metal.  The  evolution  from  the  train  of 
four  gears,  with  intermediate  shaft,  to  the  train  of  two  gears. 
(armature  pinion  and  axle  gear)  has  removed  almost  en- 
tirely the  principal  cause  for  endeavoring  to  depart  from 
the  metals  for  gear  material.  That  cause  has  been,  still  is, 
on  earlier  apparatus,  the  excessive  noise  of  the  high-speed,, 
much-worn  teeth.  It  seems  probable  that  on  the  single- 
reduction  gear  motors,  now  so  widely  introduced,  the  best 
practice  will  use  steel  wheels  with  machine-cut  teeth  both, 
on  axle  and  armature  shaft. 

(/;)  Diminution  of  noise.  This  is  connected  with  the  mat- 
ter of  (i)  speed,  (2)  material,  (3)  relative  exposure,  (4)  sus- 
pension method  for  the  whole  machine,  (5)  tooth-design,  (6) 
alignment  and  (7)  load  transmitted. 

(1)  In  designing  for  a  speed  of  about  500  armature  revolu- 
tions per  minute,  geared  to  produce  a  car  velocity  of  about 
ten  miles  per  hour,  it  is  probable  that  the  manufacturers  have 
gone  as  far  as  is  wise,  so  long  as  gears  are  used  at  all.     The 
noise  at  this  speed  may  be  inconsiderable.     The  next  step 
after  passing  the  single-reduction  motor,  geared  as  just  sug- 
gested, seems  to  be  the  gearless  or  axle  motor.     Of  its  de- 
sirability, notice  will  be  taken  later. 

(2)  As  to  material,  we  have  only  to  add  to  what  has  been 
said  above,  that  the  quietest  substitute  for  metal  thus  far 


MOTORS   AND    CAR    EQUIPMENT.  89 

found  is  wood.  This  material,  however,  is  not  strong  enough 
to  be  used  for  the  armature  pinion,  the  diameter  of  which 
scarcely  exceeds  five  inches.  Rawhide  has  been  the  most 
successful  rival  of  metal  for  this  hard  service.  In  this,  as  in 
other  substitutes,  it  has  been  difficult  to  obtain  uniform  qual- 
ity in  the  finished  product.  Consequently,  widely  different 
opinions  have  been  held  in  regard  to  its  value.  The  contest, 
we  think,  will  cease  with  the  passing  away  of  the  older 
high-speed  machines,  leaving  metal  undisturbed  in  the 
field. 

(3.)  It  is  easily  practicable  tightly  to  cover  the  gears  of  a 
single-reduction  motor.  Nor  would  the  problem  have  been 
difficult  for  the  four-gear  machines,  had  it  been  held  in  view 
during  the  original  design.  That,  however,  was  not  the  case 
in  respect  to  the  motors  most  largely  used  up  to  date,  those  of 
the  Thomson-Houston  and  of  the  Sprague  or  Edison  com- 
panies. Efforts  have  been  made  to  add  suitable  covers,  but 
every  mechanic  knows  the  difficulty  of  a  "patch  job." 

Unless  the  cover  be  very  firmly  attached,  and  of  material 
not  particularly  resonant,  its  use  may  be  of  no  benefit  in  the 
matter  of  diminishing  noise,  but  its  great  usefulness  in  ex- 
cluding dust,  pebbles,  etc.,  will  of  course  remain. 

(4)  That  form  of  motor  suspension  which  places  the  whole 
weight  of  the  machine  on  springs  will  readily  be  understood 
to  be  that  which  best  conduces  to  soft-running  gear  wheels. 
Until  very  recently,  it  has  been  an  almost  invariable  rule  to 
place  one-half  of  the  motor  weight  dead  on  the  axle,  as  ap- 
pears in  several  of  the  figures  illustrating  familiar  railway 
motors.      The  other  half  rests  on  springs  which  permit  a 
rotation  of  the  motor  around  the  axle.      This  method  has 
doubtless  been  of  more  value  in  saving  the  teeth  from  break- 
age by  sudden  strains,  than  in  diminishing  noise. 

(5)  As  to  tooth-design,   there  has  been  little  variety,  an 
approved  epicycloidal  tooth  having  been  most  largely  used. 
By  using  two   sets  of  such  teeth  on  the  same  gear,  "  stag- 
gered "  with  respect  to  each  other,  the  Edison  Company  has 
been  able  largely  to  reduce  the  rattle  often  noticed  in  well- 
worn  or  badly-adjusted  gears  of  the  double-reduction  type. 
The  design  is  shown  in  Fig.  38. 


9Q  THE    ELECTRIC    RAILWAY. 

(6)  Good  alignment  is    of  value  in  this  as  in  all  similar 

cases. 

(7)  In  the  matter  of  load  transmitted,  it  is  observed  that 
a  car  having  been  put  in  rapid  motion  by  the  work  of  the 
motor,  the  gears,  grinding  noisily  while  the  work  is  being 


;UE-EDISON  MOTOR. 


done,  become  almost  noiseless  if  the  current  is  cut  off,  though 
the  car  may  continue  its  rate  of  motion  unchanged,  as  on 
a  down  grade. 

Lubrication  of  Gear  Journals. — For  convenience,  we  may 
refer  here  to  armature  shaft  journals  also,  and  state  that 
the  best  results  have  been  had  from  the  use  of  grease  rather 
than  fluid  oil.  The  self-oiling  bearings,  such  as  are  so  widely 
used  on  dynamos,  are  not  so  well  adapted  to  service  on  a 
much-jolted  car  motor.  Oil  is  lost  rapidly  from  the  basin, 
and  it  has  seemed,  further,  that  the  feeding  rings  or  chains, 
supposed  to  revolve  eccentrically  around  the  shaft  while  dip- 
ping in  the  oil,  are  prevented  from  traveling  by  the  constant 
shocks,  which  tend  to  keep  them  playing  vertically  rather 
than  to  rotate  them.  The  grease,  placed  in  a  very  simple 
box  or  cup,  should  be  followed  by  spring  pressure  applied 
to  the  cover  or  to  some  disk  inside  the  box.  A  pin  resting 
on  the  shaft  (but  pressed  lightly,  so  that  it  will  not  cut)  and 
passing  up  through  the  body  of  the  grease,  causes  the  melted 
particles  to  follow  easily  down  its  sides. 

For  the  journals  of  the  armature  shaft,  globe  or  conical 
bearings,  as  shown  in  Fig.  39,  have  been  much  used,  while 


MOTORS   AND    CAR   EQUIPMENT.  91 

for  intermediate  and  axle  shafts  straight  bearings  have  been 
preferred. 

There  are,  however,  good  authorities  in  favor  of  straight, 
babbitted  bearings  throughout.  If  babbitt  or  other  soft 
metal  be  used,  the  greatest  care  must  be  exercised  as  to  its 
quality. 

2.  Sprocket  Chains. — Four  or  five  years  ago,  and  in  the 
practice  of  Mr.  Charles  J.  Van  Depoele,  one  of  the  earliest 
workers  in. the  field,  sprocket  chains  were  used  on  perhaps 
seventy-five  cars.  Examples  of  quite  tolerable  service  from 
these  early  machines  may  still  be  found.  The  sprocket  chain 
was  perhaps  the  best  medium  of  transmission,  as  long  as  the 
motor  remained  above  the  car  floor,  on  the  platform  or  inside 
the  car.  Nothing  better  was  available  for  covering  the  con- 
siderable distance  between  armature  shaft  and  axle.  But 
the  speed  was  high,  and  the  art  of  making  sprocket  chains 
for  such  trying  service  was  not  far  advanced.  Hence  this 
device  disappeared  when  the  motors  came  to  be  placed  under 
the  car  floor  (as  was  done  by  the  Sprague  Electric  Railway 
and  Motor  Company  in  its  earliest  work),  and  the  spur  gear 
came  to  the  front.  There  seems  good  reason  to  suppose  that 
the  chain  may  still  have  its  sphere  of  usefulness,  as  in  trans- 
mitting power  from  the  directly-driven  axle  to  a  second 
one,  the  speed  between  axles  being  less  than  elsewhere  in 
the  train.  Useful  and  apparently  successful  applications  of 


___———" 


FIG.  39.— FORMS  OF  BEARINGS. 

sprocket-chains  have  been  found  in  the  construction  of  elec- 
tric mining  machinery,  improvements  having  been  made  in 
the  manufacture  of  the  links  of  such  chains. 

3.  Bevel  Gears. — In  using  these,  the  armature  is  placed 
parallel  to  the  axis  of  the  car.  The  only  reason  for  endeav- 
oring to  do  this  is  that  one  motor  may  thus  be  connected  to 
two  axles  of  a  truck,  thus  utilizing  the  whole  weight  on  each 


92  THE    ELECTRIC    RAILWAY. 

truck  for  adhesion,  or  for  "traction,"  as  it  is  frequently  but 
improperly  expressed.  On  grades  lower  than  3  per  cent, 
this  double  connection  is  of  relatively  small  importance,  since 
on  such  grades  one-half  the  weight  of  the  car,  if  resting  on 
the  driven  wheels,  is  found  sufficient  to  prevent  skidding,  on 
average  tracks,  even  when  wet  with  snow — a  reasonable 
supply  of  sand  being  available.  For  an  ordinary  1 6-foot  car, 
operating  on  such  grades,  a  single  motor  of  such  capacity 
as  are  those  generally  rated  at  15  horse-power  (as  by  the 
Thomson-Houston,  Edison,  Short,  and  Westinghouse  com- 
panies in  the  United  States),  and  geared  to  one  axle  of  an 
ordinary  four-wheel  truck,  is  sufficient,  both  as  to  adhesion 
and  traction.  Under  favorable  track  conditions,  and  unless 
unusual  speeds  be  required,  the  same  motor  will  handle,  with- 
out slipping  and  without  overheating,  one  trail  car  of  about 
the  size  of  the  motor  car.  Where  greater  effort  is  required, 
or  under  exceptionally  bad  track  conditions,  it  is  best  to 
apply  the  driving  power  in  some  way  to  both  axles  of  a  four- 
wheel  truck ;  if  a  long  car  be  in  question,  requiring  a  six- 
wheel  truck,  or  two  four-wheel  trucks,  then  the  power  should 
be  applied  to  those  axles,  which  carry  from  70  to  90  per 
cent,  of  the  whole  weight.  As  is  familiarly  known,  this  re- 
quirement has  been  met  in  the  designs  most  widely  used  by 
using  a  separate  motor  for  each  driven  axle. 

There  was,  in  the  early  days,  four  or  five  years  ago,  some 
prejudice  in  favor  of  two  motors  per  car  for  other  reasons 
than  that  of  securing  the  needed  adhesion.  Thus  it  was 
argued  that  if  one  machine  should  be  injured,  the  other 
would  be  available  to  carry  the  car  to  the  hospital.  This  rea- 
soning supposed  a  degree  of  unreliability  in  electric  service 
which  would,  if  permanently,  inherently  true,  rule  it  out  of 
good  practice.  The  proper  reliance  in  case  of  accident  is 
upon  the  next  car  following,  and  accidents  should  be,  indeed 
are,  rare  enough  to  make  this  occasional  double  duty  unob- 
jectionable. 

In  face  of  other  manifest  advantages  of  a  single  motor, 
this  prejudice  would  soon  have  disappeared,  and  with  it  the 
double  motor  equipment  for  ordinary  cars,  except  for  this 
difficult  problem  of  sufficient  adhesion  on  heavy  grades. 


MOTORS    AND    CAR    EQUIPMENT. 


93 


The  device  of  beveled  gears  was  early  considered  and  tried, 
especially  by  Bentley  &  Knight,  who  thus  equipped  a  car  in 
1886.  But  the  mechanical  difficulties  are  great.  The  truck 
framing  must  be  rigid  to  secure  alignment  of  gears  at  the 
opposite  ends  of  the  armature  shaft ;  the  weight  of  the  motor 
must  be  practically  uncushioned,  the  efficiency  of  beveled 
gears  is  low ;  it  is  difficult  to  get  sufficiently  strong  teeth  in  a 
beveled  pinion,  of  such  diameter  and  pitch  as  required  for 
use  in  connection  with  a  3O-inch  car  wheel,  which  limits  the 


FIG.  40.— RAE  MOTOR  TRUCK. 

diameter  of  the  axle  gear  to  about  24  inches,  thus  leaving 
very  little  clearance. 

Many  students  of  the  problem  thought  these  difficulties 
such  as  to  warrant,  without  trial  of  the  beveled  gears,  the 
adoption  of  other  methods.  Recently,  however,  the  method 
lias  been  given  some  prominence  by  the  efforts  of  Mr.  Rae, 
electrician  of  the  Detroit  Electrical  Works,  Detroit,  Michigan. 
There  are  now  running  perhaps  two  hundred  cars  equipped 
by  that  company.  Curiously  enough,  they  have  been  most 
largely  used  on  comparatively  flat  roads,  where  this  peculiar 
merit  is  of  least  value,  since  on  such  roads  a  single  motor  could 
be  geared  in  the  ordinary  way.  The  weakness  of  gear  teeth 
has  given  some  trouble  in  cases  of  the  heavier  work  under- 


94  THE   ELECTRIC    RAILWAY. 

taken.  It  remains  to  be  demonstrated  whether  satisfactory 
work  will  be  had  from  similar  installations  on  very  heavy 
grades.  The  progress  of  these  efforts  will  certainly  be  a 
matter  of  great  interest.  (See  Appendix  F.) 

4.  The  use  of  connecting  rods  instead  of  gears  was  tried 
some  years  ago  by  Bentley  &  Knight,  later  by  Mr.  Leo  Daft. 
But  it  has  remained  for  Mr.  Rudolph  Eickemeyer  again  to 
call  attention  to  this  method,  by  bringing  out  at  the  same 
time  a  motor  of  such  slow  speed  that  there  is  no  reduction 
between  armature  and  axle.  The  connecting  rod  transmits 
the  power  to  the  two  axles  of  a  truck  from  a  single  armature, 
driving  forward  and  backward,  as  in  the  case  of  three  driv- 


FlG.  4i.-ElCKEMEYER   GEARLESS  MOTOR  TRUCK. 

ing  axles  of  a  locomotive  coupled  together.      (See  Fig.  41  for 
further  information.) 

[t  will  at  once  be  inquired  why,  having  reduced  the  arma- 
ture speed  to  that  of  the  axle,  Mr.  Eickemeyer  does  not  then 
center  the  armature  on  the  axle  and  avoid  any  intermediate 
mechanism.  His  reasoning  is  thus:  That  it  is  generally 

'  to  use  one  motor  rather  than  two;  that  two  motors 

I  be  needed  for  grade  work  if  the  armature  were  con- 
centric with  the  axle;  that  when  the  motor  is  placed  midway 

xm  the  two  axles  its  whole  weight  may  be  very  conven- 
itly  placed  on  springs,  a  matter  of  grave  importance,  by 

•n  of  the  cost  of  the  track  repair  due  to  the  pounding  of 


MOTORS   AND    CAR    EQUIPMENT.  95 

so  much  dead-weight ;  and  that  such  position  for  the  motor 
offers  greater  facility  in  the  matter  of  removals  than  if  on 
the  axle. 

The  few  equipments  thus  far  made  by  Mr.  Eickemeyer  have 
been  in  satisfactory  operation  for  some  months.  It  seems 
quite  clear  that  the  weight  of  these  machines  is  small,  capac- 
ity and  speed  being  duly  considered.  But  in  comparing  this 
or  any  other  motor  of  only  axle  speed  with  motors  requiring 
reduction  gearing,  it  must  be  remembered  that  the  same 
excellence  of  design  that  may  be  applied  to  the  production 
of  a  machine  of  say  20  horse-power  at  100  revolutions, 
and  weighing  5,000  pounds,  will  produce  a  machine  of  20 
horse-power  at  500  revolutions,  weighing  about  2,000  pounds, 
or  two  motors  of  10  horse-power,  weighing  about  1,200 
pounds  each.  Now,  suppose  these  two  motors  to  be  entirely 
spring-supported,  and  geared,  one  to  each  axle,  through  spur 
gearing,  in  dust-proof,  oil-tight  cases.  We  then  have,  in  the 
one  case,  one  large  motor  (more  difficult  to  handle),  5,000 
pounds  weight,  spring-supported ;  four  connecting  rods,  both 
axles  driven.  In  the  other,  two  small  motors,  2,500  pounds 
weight,  spring-supported ;  four  spur  gears ;  both  axles 
driven.  The  future  can  best  determine  which  of  these  de- 
signs will  be  generally  preferred. 

In  comparing  the  Eickemeyer  equipment  with  other  motors 
of  axle  speed,  we  are  brought  to  9 — the  direct  centering  of 
the  armature  on  the  axle.  The  most  notable  example  of 
this  method  now  in  operation  is  the  City  and  South  London 
Electric  Railway.  While,  indeed,  the  particular  feature  of 
centering  the  armature  on  the  axle  is  here  illustrated,  yet  in 
many  ways  it  is  not  a  case  properly  comparable  with  the 
efforts  no\v  being  made  in  the  United  States.  He  who  has 
felt  the  larger  freedom  which  comes  in  designing  a  separate 
locomotive,  instead  of  a. machine  placed  out  of  sight  under  a 
car  floor,  will  appreciate  the  fact  that  gearless  motors  for 
ordinary  street-railway  service  cannot  be  copied  from  the 
English  example.  We  shall,  then,  for  the  present,  return 
to  those  designs  which  have  just  been  built  in  this  country. 

Two  companies,  the  Short  Electric  Company,  of  Cleveland, 
Ohio,  and  the  Westinghouse  Electric  and  Manufacturing  Com- 


9g  THE    ELECTRIC    RAILWAY. 

pany,  of  Pittsburg,  Pa. ,  have  already  manufactured  such  gear- 
less  motors. 

The  Short  motor  has  a  "  disk  armature  "  with  pole  pieces 
on  the  sides,  familiar  in  Brush  arc-light  dynamos.  The  arma- 
ture is  attached  to  a  hollow  sleeve,  concentric  with  the  axle, 
but  supported,  through  a  framework,  on  springs,  and  of  large 
enough  inside  diameter  to  permit  vertical  play  of  about  an 
inch.  The  field  magnets  and  pole  pieces  are  supported  in 
like  manner  and  move  with  the  armature.  The  sleeve  trans- 
mits its  power  to  the  axle  through  six  cushions  or  springs 
connecting  two  pairs  of  disks,  one  keyed  fast  to  the  axle, 
the  other  fast  to  the  sleeve  (Fig.  42). 

The  design  of  the  Westinghouse  Company  shows  a  Sie- 
mens or  drum  armature  keyed  directly  to  the  axle.  The 
field  is  made  by  four  pole  pieces  connected  through  an 
external  cylinder.  The  whole  weight  of  the  motor  is  directly 
upon  the  axle  (Fig.  43). 

It  will  be  noted  that  the  Short  design  covers  the  important 
point  of  spring  suspension,  which  will  be  better  appreciated 
as  time  relentlessly  forces  attention  of  electric-railway  owners 
to  track  repair.  It  is  intended  to  use  one  motor  for  light 
grades,  and  two  for  heavy  ones,  as  above  explained.  The 
relative  merit  of  this  and  the  Eickemeyer  design  will  then  be 
determined,  in  time,  by  the  peculiarities  in  service — of  con- 
necting rods  on  the  one  hand  and  spring  connection  between 
pairs  of  disks  on  the  other. 

Ideally  simple,  the  Westinghouse  design  will  be  called 
upon  to  demonstrate  whether  or  not  some  departure  from 
such  simplicity  is  wai ranted  by  consideration  for  the  track. 

We  do  not  here  enter  into  discussion  of  the  relative  merits 
of  the  three  motors  viewed  simply  as  electric  machines  of 
greater  or  less  efficiency  and  weight  per  unit  of  output. 
Little  is  known  concerning  these  points.  That  it  is  difficult 
to  obtain  high  efficiency  at  such  low  speeds  and  in  such  lim- 
ited space  goes  without  saying.  The  necessary  limitation 
of  weight  also  raises  a  serious  question  as  to  whether  gear- 
less  motors  will  not  eventually  be  restricted  to  comparatively 
light  service,  unless  the  speed  be  considerably  higher  than 
in  ordinary  surface  tramway  service.  If  the  connecting 


MOTORS   AND    CAR   EQUIPMENT. 


97 


FIGS.  42-44.— TYPICAL  MODERN  MOTORS. 
FIG.  42.— SHORT  GEARLESS  MOTOR.    FIG.  4>— WESTINGHOUSE  GEARLESS  MOTOR. 

FIG.  44.— EDISON  SINGLE-REDUCTION  GEAR  MOTOR. 
7 


gg  THE    ELECTRIC    RAILWAY. 

rods  of  the  Eickemeyer  design,  or  the  sleeve,  springs,  and 
disks  of  the  Short  design,  are  indeed  necessary  to  save  the 
track,  we  have  at  once  a  complication  fairly  comparable  with 
the  simple  spur  gears  now  used,  and  a  total  weight,  for  a 
given  output,  considerably  greater. 

In  regard  to  (5)  worm  gears,  (6)  ordinary  belting",  (7)  ropes 
and  -pulleys,  (8)  friction  plates,  etc.,  little  need  here  be 
said.  They  have  been  used  sporadically  and  with  no  marked 
success.  The  worm  gear  is  apparently  the  best  of  these  four 
methods.  Its  low  efficiency  has  prevented  many  from  seri- 
ously studying  it.  Mr.  A.  Reckenzaun  has  constructed  a 
motor  operating  a  worm  gear,  and  has  run  the  car  by  storage 
batteries.  Details  of  his  results  have  been  published,  claim- 
ing remarkably  high  efficiency  as  compared  with  that  usually 
given  by  mechanical  authorities.  It  is  perhaps  unfortunate 
that  an  untried  gearing  should  have  been  experimentally 
associated  with  storage  batteries.  It  is  hardly  fair  toward 
the  gearing. 

(B)  Convenience  of  position  with  respect  to  inspection, 
repair  and  removal.  In  the  earlier  electric-railway  practice 
numerous  examples  are  found  in  which  the  consideration 
of  accessibility  seems  to  have  been  treated  as  important. 
Motors  were  placed  on  the  platform  of  the  car,  in  the  body 
of  the  car,  or  in  a  separate  cab.  The  desire  to  use  spur 
gears,  and  to  leave  untouched  th'e  space  available  for  pas- 
sengers, caused  the  Sprague  Company  to  place  motors  under 
the  car  floor;  and  there  they  remain  in  the  general  practice 
of  to-day.  The  position  is  one  of  the  greatest  exposure  to 
dirt  and  to  foreign  objects  that  may  cause  immediate  de- 
struction ;  it  also  makes  repairing  a  difficult  matter.  Never- 
theless, it  is  the  right  position,  pointed  out  alike  by  mechan- 
ical and  commercial  reasons.  Recent  improvements  in  the 
reliability  of  motor  windings,  in  the  mechanical  construction 
of  motor  frames,  in  the  simplicity  and  protection  given  the 
gearing  —  all  combine  to  diminish  the  troubles  resulting- 
from  this  difficult  position'.  If  separate  locomotives  are  used, 
the  armature  must  still  be  concentric  with  the  axle,  or 
removed  from  it  only  by  one  train  of  gears.  The  general 
body  of  the  motor  may,  however,  be  extended  vertically, 


MOTORS   AND    CAR   EQUIPMENT. 


99 


FIGS.    45-47.-TYPICAL   MODERN    MOTORS. 

FIG.  45.— THOMSON-HOUSTON    'WATER-PROOF"  MOTOR.    FIG.  46.— SHORT  SINGLE-RE- 
DUCTION GEAR  MOTOR.   FIG.  47.— THOMSON-HOUSTON  SINGLE-REDUCTION  GEAR  MOTOR. 


100  THE    ELECTRIC    RAILWAY. 

instead  of  horizontally,  as  now;  or  it  may  lie  between  these 
two  positions,  as  in  the  City  and  South  London  Railway  loco- 
motives. This  arrangement,  of  course,  makes  the  machines 
much  more  accessible. 

It  has  been  thought  by  some  that  separate  locomotives 
would  eventually  be  introduced  into  the  street  service  of 
great  cities.  This  does  not  seem  probable.  To  bring  it 
about  means  to  introduce  greater  dead-weight  per  passenger 
carried,  greater  expenditure  of  power,  greater  difficulty  as 
to  adhesion,  and  greater  street  obstruction.  For  suburban 
service,  or  for  elevated  or  underground  railways,  in  which 
several  cars  are  to  be  run  in  a  train  over  easy  grades,  the 
problem  is  widely  different,  and  seems  to  call  for  the  separate 
construction. 

It  may  also  appear  in  a  sort  of  compromise  case  as  follows: 
a  suburban  line  feeds  a  main  cable  line ;  cars  are  brought  to 
and  from  the  latter  by  an  electric  motor  car  having  perhaps 
a  few  seats  for  smokers.  This  method  has  already  been 
proposed  for  one  of  our  large  cities. 

CAR   TRUCKS. 

Some  of  the  earlier  installations  show  the  motor  hung  on 
the  axle  on  one  side,  and  suspended  by  springs  directly  from 
the  car  body  on  the  other.  This  method  was  applied  to  cars 
that  had  been  built  for  propulsion  by  horses,  and  required  no 
change  save  an  enlarging  of  the  axle  and  a  strengthening  of 
the  floor  beams.  Subsequent  practice  has,  however,  devel- 
oped a  different  method,  now  almost  universally  used.  The 
wheels  and  axles  are  mounted  in  a  frame  which  carries  a 
cross-bar  for  the  support  of  the  motor,  and  springs  which 
receive  directly  the  weight  of  the  car  body  and  cushion  its- 
oscillations.  This  separate  truck  offers  facilities  for  mounting 
and  dismounting  motors,  for  exchange  of  car  bodies  (as 
between  open  and  closed),  and  in  a  convenient  manner  sup- 
plies the  strength  of  frame  needed  for  the  support  of  the 
motor.  A  great  variety  of  designs  may  now  be  seen,  differ- 
ing rather  in  detail  than  in  any  important  principle.  It  is 
gratifying  to  note  in  the  later  designs  a  simplicity  of  con- 
struction which  was  not  observable  in  the  earlier  forms. 


MOTORS   AND    CAR   EQUIPMENT. 


IOI 


FIG.  48. 


FIG.  49. 


FIG.  50. 


FIG 


TYPICAL  ELECTRIC  STREET-CAR  TRUCKS. 

PIG.  48.-BRILL  TRUCK     FIG  49.-MASiF.R  TRUCK     FIG.  5o.-BRiLL  MAXIMUM  TRACTION 
BOGIE  TRUCK.     FIG  SI.-STEFHF.NSON  BOGIE  TRUCK. 


I02  THE    ELECTRIC    RAILWAY. 

Nuts,  bolts,  screws,  even  rivets,  should  all  be  considered  as 
.evils sometimes  necessary,  but  to  be  kept  down  to  a  mini- 
mum in  numbers.  There  is  room  for  endless  discussion 
concerning  the  details  of  truck  design,  but  the  scope  of  this 
book  permits  that  only  some  of  the  more  familiar  types  shall 
be  shown,  as  in  Figs.  48  to  56. 

During  the  last  year,  there  has  been  a  very  rapid  increase 
in  the  use  of  larger  cars  than  the  standard  horse-car,  which 
may  be  said  to  be  that  having  a  1 6-foot  body.  These  larger 
cars  have  brought  with  them  the  double  truck  and  its  varia- 
tions. Since  the  maximum  allowable  wheel  base  may  be 
said  to  be  7  feet,  it  is  evident  that  in  going  much  beyond  a 
1 6-foot  body,  it  becomes  necessary  to  use  more  than  two 
axles,  as  the  overhang,  and  consequent  "teetering,"  would 
otherwise  be  excessive.  Steam-railway  practice  affords 
abundant  precedent  in  the  matter  of  double-truck  cars,  but 
some  of  the  conditions  for  electric  service  are  new.  These 
are  mainly  the  provision  of  suitable  space  and  framing 
members  for  motor  support,  provision  for  sharper  curvature 
than  is  ever  met  with  in  steam  practice,  and  especially 
important  is  the  problem  of  throwing  a  large  part  of  the 
total  weight  of  the  car  on  two  axles,  instead  of  equally 
dividing  it  over  the  four  axles  of  two  trucks,  as  in  general 
steam-railway  practice.  It  is  not  desirable  to  multiply  the 
number  of  motors  on  any  one  car ;  it  is  desirable — necessary, 
indeed — that  the  driven  axles  should  bear  such  weight  as  will 
prevent  skidding  of  the  wheels.  On  wet,  especially  snowy, 
rails  the  frictional  resistance  between  wheel  and  rail  is  found 
at  times  as  low  as  one -tenth  of  the  total  weight  on  the 
wheels.  That  is  to  say,  if  an  effort  of  200  pounds  per  ton 
were  required  to  start  a  car  resting  its  whole  weight  on  the 
driven  wheels,  these  wheels  may  slip  if  the  rails  be  wet. 
If  the  rails  be  dry,  the  wheels  may  not  slip  until  a  horizontal 
effort  equivalent  to  0.35  of  their  load  has  been  applied;  or, 
expressed  in  pounds  per  ton,  they  may  slip  when  the  hori- 
zontal effort  is  700  pounds  per  ton. 

^Experience  shows  that  on  a  level  track,  with  ordinary  run- 
ning gear,  an  effort  of  about  70  pounds  per  ton  is  required  to 
start  a  car— this  overcoming  the  inertia  and  friction  of  the 


MOTORS    AND    CAR    EQUIPMENT. 


103 


FIG.  52. 


FIG.  53. 


FIG.  54. 


FIG.  55. 


FIG  56. 
TYPICAL    ELECTRIC    STREET-CAR   TRUCKS. 

FIG.  52.— STEPHENSON  TRUCK.    FIG.  53.— ROBINSON  RADIAL  TRUCK.    FIG.  54.— TAYLOR 
TRUCK.    FIG.  55.— PECKHAM  CANTILEVER  TRUCK.    FIG.  56.— McGuiRE  TRUCK. 


I04  THE   ELECTRIC    RAILWAY. 

parts.  On  grades,  add  20  pounds  per  ton  for  each  i  per  cent, 
of  grade  to  give  the  starting  effort.  Thus,  on  a  3  per  cent, 
grade  the  starting  effort  =  70  +  (20  X  3)  =  i  3O  pounds.  Since 
200  pounds  may  be  the  lower  limit  of  adhesion,  we  may  cal- 
culate that  on  a  grade  of  -  ^Q  7'-  —  6.5  per  cent,  the  wheels 

may  slip,  though  the  whole  weight  of  the  cars  be  on  the 
driven  axles,  as  in  the  ordinary  1 6-foot  single-truck  car 
carrying  one  motor  on  each  axle!  A  similar  calculation 
shows  that  if  only  half  of  the  total  weight  be  on  the  driven 
axle,  or  axles,  there  may  be  slipping  at  the  start,  on  a  1.5 
per  cent,  grade.  The  adhesion  in  this  case  for  the  driven 
axles  is  only  100  pounds  per  ton  of  total  weight;  of  this  take 
70  pounds  for  starting  on  a  level,  leaving  30  pounds  per  ton 
for  gravity  resistance,  which  would  be  met  on  a  grade  of  1.5 
per  cent.  When  once  under  way,  the  horizontal  effort  per 
ton,  exclusive  of  gravity  effect,  may  be  taken  at  30  pounds 
as  a  high  figure  for  ordinary  conditions.  We  have,  then, 
when  the  car  is  in  motion,  as  possible  slipping  grades,  for  the 

whole  weight  on  "the  driven  axles,—      — -- =  8.5  per  cent., 

for  half  the  weight  on  the  driven  axles,  —      — —  =3.5  per 

cent. 

Fortunately,  the  conditions  here  supposed  are  rare,  but  the 
sand  box  should  be  filled  in  order  to  meet  them.  If  either 
the  start  or  the  run  must  be  made  on  a  curve  or  on  a  very 
rough  track  (or  on  both),  the  figures,  70  pounds  and  30 
pounds,  for  starting  and  maintaining  speed,  respectively, 
may  be  exceeded,  and  the  grades  of  possible  slipping  cor- 
respondingly diminished. 

Examples  may  be  given  of  cars  in  daily  operation  on 
grades  as  high  as  13  per  cent.  Sand  is  frequently  used. 
The  cars  have  ordinary  four-wheel  trucks,  a  motor  on  each 
axle.  There  is  rarely  any  commercial  demand  for  operation 
over  any  heavier  grades. 

For  single-truck  cars  we  may,  then,  summarize  the  case  as 
follows: 

For  summer  service  (i.e.,  when  rails  are  generally  in  good 


MOTORS   AND    CAR   EQUIPMENT.  10$ 

condition)  on  grades  up  to  5.0  per  cent.,  and  for  winter  ser- 
vice on  grades  up  to  3  per  cent.,  the  required  adhesion  may 
be  had  from  one  driven  axle.  On  grades  above  5  per  cent, 
for  summer  and  3  per  cent,  for  winter  both  axles  must  be 
driven;  this  may  be  done  by  using  two  motors,  as  is  now 
ordinarily  the  case,  or  by  some  connection  of  a  single  motor 
to  both  axles,  should  any  method  of  accomplishing  this  prove 
successful. 

The  case  of  the  long  cars  may  be  thus  stated.  For  the 
lower  grades,  as  above  mentioned,  for  summer  and  winter 
respectively  (requiring  only  half  of  the  total  weight  to  be  on 
the  driven  axles),  adhesion  may  be  had  (a)  by  gearing  a 
motor  to  each  of  the  two  axles  of  one  of  the  two  ordinary 
trucks;  (b)  or  by  gearing  one  motor  to  one  of  the  axles  of 
each  of  the  two  ordinary  trucks ;  (c)  or  by  gearing  one  motor 
to  both  axles  of  one  of  the  two  trucks  used,  if  such  gearing 
can  be  perfected. 

For  the  heavier  grades  (requiring  all  or  nearly  all  the 
weight  to  be  on  driven  axles)  the  requisite  adhesion  may  be 
had  (a)  by  gearing  one  motor  to  each  of  the  axles  of  the 
two  ordinary  trucks,  making  four  motors  in  all;  (b)  by 
gearing  one  motor  to  both  axles  of  the  two  trucks,  if  such 
gearing  is  successful ;  (c)  by  using  two  trucks,  modified  in  such 
a  way  that  one  axle  of  each  shall  carry  nearly  all  the  weight 
of  one-half  of  the  car,  this  axle  having  a  motor  geared  to  it ; 
the  other  axle  carrying  only  enough  weight  to  keep  it  on  the 
track,  and  having  no  motor  geared  to  it;  (d)  by  using  only 
three  axles  altogether,  those  under  the  ends  of  the  car  to 
carry  nearly  all  the  weight,  and  having  a  motor  geared  to 
each — the  middle  axle  serving  only  as  a  guide,  and  carrying 
no  motor.  The  first  method  (a)  is  objectionable  by  reason 
of  the  great  number  of  parts  to  be  maintained  and  the  rela- 
tively greater  losses  in  transmission  of  power  to  the  axles. 
The  second  (b)  has  not  been  generally  demonstrated.  The 
third  (c)  may  utilize  90  per  cent,  of  the  total  weight,  and  has 
been  successfully  applied  on  considerable  grades,  through 
what  is  called  the  "maximum  traction  truck." 

The  fourth  (d)  may  utilize  about  90  per  cent,  of  the  whole 
weight,  and  has  been  successfully  applied  on  considerable 


IO6  THE   ELECTRIC    RAILWAY. 

grades  through  what  is  called  the  "radial  truck."  To 
further  explain  these  last  two  methods,  Figs.  50  and  53  are 
given,  showing  the  trucks  mentioned.  Both  these  designs 
are  of  great  importance.  As  compared  with  ordinary  truck 
construction,  they  represent  a  departure  which  seems  essen- 
tial to  the  application  by  present  methods  of  spur-geared 
motors  to  long-car  service  (20  to  35  foot  bodies)  on  grades 
above  5  per  cent.  The  use  of  a  sprocket  chain,  connecting 
the  motor  axle  with  an  empty  axle  (as  recently  designed  for 
some  special  cases) ,  may  indeed  serve  the  same  purpose ;  its 
success  has  yet  to  be  demonstrated.  The  efforts  about  to  be 
made  should  be  watched  with  great  interest.  Further,  it  is 
of  course  possible  to  use  four  motors  on  trucks  of  ordinary 
construction.  This  method  has,  indeed,  been  proposed  by  a 
large  railway  company,  for  covering  its  winter  service  on 
slippery  tracks ;  in  summer,  one  motor  truck  is  to  be  replaced 
by  an  empty  truck  taken  from  a  summer  or  open  car;  the 
motor  truck  thus  borrowed  is  to  be  put  under  the  open  car, 
which  would  thus  be  ready  for  service.  The  closed  car,  when 
needed  during  the  summer,  could  also  be  run  by  its  remain- 
ing motor  truck.  In  other  words,  both  classes  of  cars,  open 
and  closed,  would  at  any  time  during  the  summer  be  ready 
for  immediate  service — the  total  equipment,  counting  both 
classes,  being  only  two  motors  per  car.  Further,  it  is  argued 
that  the  tractive  power  and  the  adhesion  against  slipping 
are  thus  both  kept  in  a  reasonable  proportion  to  the  demand, 
which,  for  both,  is  greater  in  winter  than  in  summer. 

It  was  also  proposed  that  the  individual  weight  and  capacity 
of  the  motors  might  be  diminished  as  compared  with  present 
standards.  If  each  motor  were  of  10  horse-power  capacity, 
then  in  summer  each  car  would  have  a  total  of  20  horse- 
power, and  in  winter  a  total  of  40  horse-power — the  supply 
in  both  cases  being  considered  sufficient  for  grades  not  ex- 
ceeding 5  per  cent.,  and  for  a  schedule  speed  of  about  8 
miles  per  hour,  including  stops,  the  cars  in  question  being 
about  28  feet  long  in  the  body.  While  this  method  has 
some  advantages,  yet  on  account  of  the  objection  to  multipli- 
cation of  motors  already  pointed  out,  it  does  not  seem  as 
desirable  as  that  based  on  the  use  of  trucks  such  as  the  max- 


MOTORS   AND    CAR   EQUIPMENT.  1 07 

imum  traction  type,  limiting  to  two  the  number  of  motors 
per  car,  winter  and  summer. 

If  it  be  still  required  that  open  and  closed  cars  shall  be  in 
constant  readiness  during  the  summer,  two  methods  are 
open.  If  the  grades  are  light,  one  motor  may  at  the  open- 
ing of  warm  weather  be  transferred  to  the  open  cars,  each 
car  thus  having  for  summer  work  one  motor  of,  say,  20  horse- 
power capacity.  If  the  grades  be  heavy,  requiring  even  in 
summer  much  more  than  half  the  weight  to  be  on  the  driven 
axles,  then  a  double  equipment  of  two  motors  per  car  may 
be  had,  each  of,  say,  15  horse-power  capacity.  If  one  motor 
can  be  successfully  geared  to  the  axles  of  a  truck  as  by 
sprocket  chains,  by  gearing  or  connecting  rod,  the  shifting 
of  one  "  live  "  truck  from  the  closed  to  the  open  car,  as  above 
described,  would,  for  the  lower  grades,  produce  the  desired 
result  of  having  both  classes  of  cars  in  readiness  during  the 
summer  months.  If  this  condition.be  required  on  roads  of 
heavier  grade,  a  complete  independent  equipment  must  be 
provided  for  open  and  closed  cars,  no  matter  how  the  motors 
may  be  connected  to  the  axles.  It  is  not  probable  that  such 
an  expense  would  be  incurred  by  many  companies;  they 
would  in  general  prefer  to  run  only  the  closed  cars,  or  to  run 
the  open  cars  with  curtains  down  during  summer  rains ;  or, 
again,  to  run  the  open  cars  only  as  trailers.  This  latter 
method  has  the  disadvantage  of  attracting  the  live  load  away 
from  the  motors,  thus  making  more  difficult  the  problem  of 
adhesion. 

TROLLEYS. 

To  obtain  a  satisfactory  "  running  contact  "  was  four  years 
ago  a  serious  question.  To-day,  the  trolley  apparatus  as  a 
whole  is  in  a  satisfactory  condition.  A  brass  grooved  wheel 
about  five  inches  in  diameter  is  centered  on  rawhide  or 
graphite  journals,  and  mounted  at  the  end  of  a  pole  about  12 
feet  long ;  this  pole  trails  back  from  the  middle  of  the  car 
roof  at  an  angle  of  about  30  degrees  with  the  vertical,  when 
the  trolley  wire  is  18  feet  above  the  ground;  it  is  pivoted,  a 
few  inches  from  the  lower  end,  in  a  frame  attached  to  the 
car  roof,  and  springs  acting  at  the  lower  end  press  the  wheel 


io8 


THE    ELECTRIC    RAILWAY. 


against  the  trolley  wire ;  by  expansion  or  contraction  of  these 
springs,  the  pressure  is  continued  as  the  height  of  the  wire 
varies ;  by  a  cam  arrangement,  the  lever  arm  through  which 
the  springs  act  against  the  pole  may  be  changed  in  such  a 
way  as  to  keep  the  pressure  against  the  wire  nearly  constant, 
whatever  the  degree  of  compression  or  expansion  of  the 
operating  springs.  This  general  description  covers  a  num- 
ber of  satisfactory  forms  varying  in  detail.  The  pole  may 
be  of  wood  or  steel ;  the  steel  may  be  straight,  tubular,  in 
sections  of  different  diameter,  or  drawn  tapering  in  one 
piece ;  the  current  may  pass  through  the  journal  of  the  wheel 
or  be  taken  through  brushes ;  thence  it  may  go  through  the 


I J 


FIG.  57.— UNDERRUNNING  ROD  TROLLEYS. 

pole,  insulated  at  its  base  to  the  wire  leading  to  the  motor; 
or  it  may  pass  from  the  wheel  to  an  insulated  wire  passing 
through  the  pole. 

Two  variations  from  this  general  form  are  important.  In 
one,  the  wheel  just  mentioned  is  replaced  by  a  shoe  which 
slides  against  the  wire.  Usually  a  lining  of  soft  metal  is 
placed  in  the  shoe,  being  replaced  every  day  or  two  at  an 
expense  of  about  one  cent.  This  has  been  used  by  the  Short 
Electric  Company  and  seems  to  have  given  satisfaction.  In 
the  other  the  wheel  is  replaced  by  a  straight  bar  of  consider- 
J  length,  placed  at  right  angles  to  the  pole  and  to  the 


MOTORS   AND    CAR    EQUIPMENT.  109 

longer  axis  of  the  car.  To  prevent  the  possibility  of  trouble 
at  crossings  and  switches,  while  doing  away  with  overhead 
frogs,  this  bar  or  cylindrical  rod  should  be  cuived  down  at 
its  ends,  or  the  "  T  "  form  should  be  replaced  by  an  inverted 
"U."  (See  Fig.  57.) 

This  "  T  "  form  has  lately  been  brought  forward  by  Sie- 
mens &  Halske.  It  was  used  in  1887  by  the  Sprague  Electric 
Railway  and  Motor  Company,  and  sacrificed,  perhaps  need- 
lessly, to  the  desire  to  please  in  the  matter  of  looks.  While 
the  action  of  the  trolley  wheel  is  on  the  whole  satisfactory,  it 
would  certainly  be  a  great  gain  in  line  construction  to  drop 
the  use  of  frogs,  cross-overs,  etc. 

A  few  typical  forms  are  shown  in  Figs.    58  to  63. 

CAR   WIRING. 

As  to  the  car  wiring,  it  may  be  thus  briefly  described. 
There  are  independent  circuits  between  the  trolley  and  the 
rails,  one  for  lamps,  one  for  motors,  one  for  the  lightning  ar- 
rester, and  there  may  be  one  for  heaters.  In  the  lamp  circuit 
there  may  be  placed  in  series  16  candle-power  lamps,  each  at 
normal  brilliancy  when  it  has  about  100  volts  between  its 
terminals.  Since  the  line  potential  is  approximately  500 
volts,  if  more  than  five  lamps  be  required,  they  must  be  of 
lower  voltage  than  100,  or  another  circuit  must  be  made. 

The  motor  circuit  is  itself  in  duplicate  when  the  motors 
are  in  multiple,  and  may  indeed  be  said  to  be  constituted  of 
two  circuits.  One  must  of  course  vary  its  wiring  according  to 
the  system  of  regulation  employed.  Fig.  64  shows  the  stand- 
ard wiring  of  the  Thomson- Houston  Company.  Fig.  65  shows 
that  of  the  Edison  Company.  In  the  motor  circuit  are  placed 
the  safety  fuses  and  controlling  switches.  As  to  the  use  of 
these,  consult  the  rules  of  practice  given  elsewhere.  Elec- 
tric heaters  have  not  come  into  very  general  use,  but  may 
grow  in  favor.  Thus  far  the  practice  has  been  to  place  two 
or  more  heaters  in  multiple,  in  the  first  few  hours  of  service, 
causing  a  current  of  about  6  amperes  to  flow.  When  the 
car  has  been  well  warmed,  the  heaters  are  thrown  into  the 
series  arrangement,  reducing  the  current  to  about  3  amperes. 
It  is  said  that  this  quantity  of  current  will  keep  a  1 6-foot 


no 


THE   ELECTRIC    RAILWAY. 


FIG.  62. 
TROLLEYS  AND   TROLLEY   BASES. 


FIG.  63. 


FIG.  58.— SHORT  SLIDING  TROLLEY.  FIG.  SQ.-BAKER  TROLLEY.  FIG.  60.— SHORT  TROL- 
LEY. FIG.  61.— "BOSTON"  TROLLEY.  FIG.  62.— LIEB  TROLLEY  BASE.  FIG.  63.— 
"  COMMON  SENSE  "  TROLLEY  BASE. 


MOTORS   AND    CAR    EQUIPMENT. 


1  I  I 


car  at  a  comfortable  temperature  in  very  severe  weather. 
Its  cost  may  be  roughly  estimated  on  this  basis.  One  ampere- 
hour  will  cost  from  0.8  cent  to  1.5  cents.  For  convenience, 
say  i.o  cent.  If  during  an  eighteen-hour  run  the  current 
averages  4  amperes,  then  the  cost  per  day  for  the  supply 
of  fuel  would  be  72  cents.  The  expenditure  for  fuel  in  heating 
by  stoves  may  be  taken  at  about  10  cents. 

Cleanliness  and  convenience  are  of  course  great  considera- 


ARTICLE 

ARTICLE 

ARTICLE 

BOX  (4  AMP.FUSE  WIRE  ) 

? 

H 

—  ™—  >' 

2 

N 

FIG.  64.— THOMSON-HOUSTON  CAR  WIRING. 

tions  in  favor  of  the  electric  heaters.  These  have  been  made 
by  imbedding  wire  or  other  metallic  conductors  in  clay  or  a 
similar  substance,  the  whole  being  then  inclosed  in  an  iron 
case  which  may  be  placed  under  the  seats.  The  clay,  by 
preventing  oxidation,  permits  a  relatively  larger  current  to 
flow  through  a  conductor  of  given  cross-section,  without 
destroying  it. 


112 


THE   ELECTRIC    RAILWAY 


FIG.  65.-EDisoN  CAR  WIRING. 


MOTORS   AND    CAR    EQUIPMENT. 


LIGHTNING   ARRESTERS. 

The  device  used  to  protect  the  machinery  from  lightning 
constitutes  normally  what  is  often  called  an  open  circuit.  In 
its  simplest  form,  the'  lightning-arrester  circuit  would  show 
simply  a  break  of  say  one-eighth  of  an  inch  between  two 
points.  In  Fig.  66  this  simple  circuit  is  shown,  and  in  its 
relation  to  the  other  circuits  of  the  car. 

It  has  been  demonstrated  by  experience,  that  if  a  high 
potential  be  suddenly  established  at  a  point,  A,  Fig.  66,  it  can 
more  readily  force  a  current  across  a  break,  B  (of  suitable 
dimensions),  than  through  the  complicated  windings  of  wire 
around  metal  masses,,  which  together  constitute  the  motors. 


FIG.  66.— LIGHTNING-ARRESTER  CIRCUIT. 

A  steady  and  moderate  potential,  such  as  that  supplied  from 
the  dynamos,  is  on  the  other  hand  unable  to  force  a  current 
across  the  air  space,  B,  but  sets  up  a  proper  current  through 
the  motors. 

The  motor  current  thus  produces  in  the  two  cases  effective 
resistances,  varying  widely  as  compared  with  that  of  the  air 
gap.  This  is  traced  to  the  self-induction  of  a  path  containing 
many  convolutions. 

Seeking  some  analogy  with  more  familiar  mechanical  phe- 
nomena, we  may  liken  this  to  the  resistance  known  as  inertia, 
or  the  resistance  to  change  of  state.  Its  measure  is  the 
measure  of  the  work  required  to  change  the  velocity  of  a 
given  mass  by  a  given  number  of  units  of  velocity  in  a  given 
time ;  it  is  the  time  element  which  operates  to  our  advantage 
in  the  lightning  discharge.  The  high  potential  at  A  can 


II4  THE    ELECTRIC    RAILWAY. 

establish  an  arc  at  B  in  shorter  time  than  it  can  establish  a 
current  through  the  motor  windings.  The  arc  having  been 
established,  the  high  potential  is  at  once  lowered  by  the  flow 
to.  earth,  there  being  nothing  now  to  maintain  a  higher 
potential  than  500  volts.  If  between  the  trolley  wire  and 
the  ground  no  other  circuit  be  prepared  than  that  through 
the  motors,  then  the  discharge  would  force  itself  through 
some  point  in  the  windings  where  the  insulation  resistance 
between  the  wire  and  the  body  of  the  motor  or  between  the 
wire  and  the  general  metal  of  the  car  (equivalent  to  earth)  is 
low. 

Whether  there  is  a  lightning  arrester  or  not,  it  is  best  to 
connect  the  field  windings  next  to  the  trolley  wire,  since  the 
discharge  generally,  though  not  always,  enters  from  over- 
head  injury  to  the  fields  being  less  serious  than  injury 

to  the  armature. 

The  arc  at  B  having  been  established,  and  the  motor  thus 
protected  from  Lne  destructive  effect  of  the  discharge,  a  new 
trouble  arises,  necessitating  some  means  of  quickly  destroy- 
ing the  arc  itself.  This  arc,  or  body  of  heated  gas  between 
the  points  at  B,  is  of  very  low  resistance  as  compared  with 
the  cold  air  previously  separating  them.  The  ordinary  press- 
ure on  the  line  (500  volts)  is  therefore  able  to  maintain  this 
arc,  and  will  cause  a  very  great  current  to  flow  over  this  path, 
practically  short-circuiting  the  motors. 

The  current,  even  if  not  great  enough  to  melt  the  wires 
leading  to  and  from  B,  becomes  great  enough  to  materially 
lower  the  potential  at  A,  thus  checking,  perhaps  stopping, 
the  motors,  and  causing  a  waste  of  energy.  The  effort  to 
prevent  this  secondary  action  has  produced  various  lightning 
arresters  now  on  the  market.  Underlying  nearly  all  these 
forms  may  be  found  one  of  these  two  principles.  First :  to 
destroy  the  arc  by  magnetic  action  repelling  or  attracting, 
and  thus  weakening  it.  Second:  to  lengthen  the  air  gap 
so  much  that  the  arc  cannot  be  maintained  across  it. 

If  the  latter  method  be  employed,  means  must  be  devised 
for  resetting  the  points  with  the  proper  distance  between 
them,  or  setting  new  points  in  position  for  the  passage  ot 
another  discharge.  In  the  first  method,  the  pole  of  a  magnet 


MOTORS   AND    CAR    EQUIPMENT. 


Is  placed  near  the  air  gap,  and  when  the  arc  is  formed  the 
reaction  between  the  lines  of  force  surrounding  the  magnet 
and  those  surrounding  the  arc  strains  the  latter  to  the  point 
of  disruption.  Unless  the  heat  should  cause  the  metal  points 
to  "  bead,"  and  possibly  to  bridge  over  the  gap,  this  device  is, 
of  course,  constantly  ready  for  action.  If  the  strength  of  the 
magnet  be  properly  proportioned,  this  beading  can  scarcely 
occur.  As  a  further  precaution,  the  points  may  be  of  carbon, 
although  their  disintegration  by  the  heat  may  increase  the 
gap  until  the  device  becomes  useless.  One  of  the  most  suc- 
cessful of  the  devices  in  which  new  points  are  put  in  position 
after  every  discharge  is  theWasson  arrester.  The  arc  forms 
between  carbon  buttons  and  the  passage  of  the  current 


FIG.  67.— WESTINGHOUSE  LIGHTNING 
ARRESTER. 


FIG.  68.— WIRT  LIGHTNING 
ARRESTER. 


melts  successively  the  fuses,  causing  a  lever  to  drop  into  the 
series  of  positions  which  bring  the  successive  couples  of 
carbon  buttons  very  near  together.  In  resetting  the  lever  to 
its  original  position,  the  buttons  may  be  rotated  to  place  fresh 
portions  of  their  circumferences  in  the  position  of  nearest 
approach.  This  device  seems  to  take  care  of  as  many  dis- 
charges as  there  are  carbon  couples  which  may  be  conven- 
iently placed  in  the  box,  say  four  or  five.  In  another  device 
the  sudden  expansion  of  a  body  of  air,  due  to  the  heat  of  the 
arc,  caused  an  arm  to  rotate,  as  from  A  to  B,  Fig.  67,  bring- 
ing C  and  D  successively  into  position  in  the  compartments 


!  jg  THE    ELECTRIC    RAILWAY. 

E  and  F,  respectively.  This  ingenious  apparatus  has  not 
been  so  widely  tested  as  to  demonstrate  its  relative  or  its 
absolute  merit. 

In  the  Wirt  arrester,  Fig.  68,  there  is  a  departure  from  the 
methods  just  described,  in  this :  that  the  arc  is  supposed  not 
to  be  formed  at  all.  It  consists  of  a  number  of  thin  metal 
plates  laid  alternately  with  thin  sheets  of  insulation,  the 
whole  arranged  in  compact  cylindrical  shape.  One  end  plate 
is  connected  to  line,  the  other  to  ground.  In  order  to  com- 
plete a  circuit  through  this  system  of  plates,  the  current  must 
jump  from  the  periphery  of  the  first  plate  to  that  of  the  sec- 
ond, then  on  to  the  third,  etc.  After  proper  experiment,  a 
certain  number  and  thickness  of  plates  and  insulating  sheets  is 
found,  such  that  the  dynamo  current  cannot,  while  the  ordinary 
lightning  discharge  can,  force  its  way  from  edge  to  edge  of 
the  plates.  That  ordinarily  no  arc  is  formed,  is  due  to  the 
fact  that  each  of  the  many  air  gaps  is  very  short,  while  its 
breadth  (equal  to  the  circumference  of  the  disk)  is  consider- 
able. Occasionally  there  has  been  some  "  beading "  across 
from  plate  to  plate,  producing  finally  a  short  circuit  with 
respect  to  the  motors.  Generally  speaking,  however,  this 
device  is  reliable,  and  has  the  advantage  of  compactness  and 
economy. 

The  principle  of  "dividing  the  arc,"  exemplified  in  this 
arrester,  is  important,  and  has  other  useful  applications. 

GENERAL   INSTRUCTIONS   FOR   THE   CARE   OF    MOTORS. 

It  should  be  well  understood  that  it  is  as  necessary  properly 
to  care  for  electric  motors  as  that  a  locomotive  should  be 
kept  clean  and  in  good  working  order.  Careful  attention 
given  to  all  the  parts  of  any  piece  of  machinery  insures  to  it 
longer  life  and  from  it  better  service.  Electric  -  railway 
motors  have  a  very  hard  duty  to  perform.  Rough  and  dirty 
tracks,  severe  strains,  heavy  loads,  etc.,  all  tend  to  wrench 
and  shake  the  motors  to  pieces,  and  it  is  therefore  very  nec- 
essary that  every  individual  part  of  the  apparatus  should 
receive  the  most  careful  attention.  In  order  that  this  matter 
maybe  well  understood  and  emphasized,  we  have  arranged  a 
number  of  rules,  which,  if  followed  in  their  spirit,  we  believe 


MOTORS   AND    CAR    EQUIPMENT.  I  I/ 

will  greatly  aid  those  to  whom  the  care  of  motors  is  given  in 
keeping  the  apparatus  in  the  best  possible  condition. 

There  are  so  many  manufacturers  making  electrical  rail- 
way apparatus,  and  these  change  so  frequently,  in  greater 
or  less  degree,  the  details  of  their  apparatus,  that  it  is  impos- 
sible to  give  to-day  any  set  of  rules  which  may  not  in  consid- 
erable part  be  inapplicable  within  the  next  few  months.  It 
must  always  remain  necessary  that  the  more  minute  instruc- 
tions required  for  the  operation  of  apparatus  shall  be  obtained 
directly  from  the  manufacturer  of  that  apparatus. 

The  rules  given  we  therefore  call  "  General  Instructions 
for  the  Care  of  Motors,"  and  they  are  as  follows: 

A.  Inspection  of  cars  and  their  preparation  for  service. 

The  motors  should  be  thoroughly  cleaned  and  all  oil, 
grease,  dust,  etc.,  wiped  from  them;  and  all  oil  wells  and 
grease  cups  should  be  filled.  The  armatures,  commutators, 
and  brush  holders  should  receive  especial  care.  An  accu- 
mulation of  dust  and  oil  is  a  good  inducement  for  short  cir- 
cuits. All  parts  should  be  kept  as  dry  and  clean  as  possible ; 
a  very  little  vaseline  or  paraffme  on  the  commutator,  how- 
ever, if  carbon  brushes  are  used,  lengthens  the  life  of  the 
brushes  and  seems  to  diminish  the  noise. 

All  nuts  and  bolts  should  be  carefully  inspected  and  seen 
to  be  tight  and  in  their  proper  places.  Keep  the  gearing  as 
free  from  dirt  as  possible.  Many  motors  now  have  their 
gears  inclosed  in  an  oil  bath,  which  besides  diminishing  the 
noise  keeps  the  gearing  in  very  good  condition. 

Examine  the  wiring  of  the  car  to  see  that  the  connections 
are  correctly  and  securely  made  and  the  insulation  of  the 
wires  intact.  See  that  the  controlling  apparatus  is  in  good 
condition ;  this  is  very  important,  and  too  much  care  cannot 
be  taken  to  see  that  all  controlling  mechanisms,  switch  boxes, 
rheostats,  reversing  switches,  etc.,  are  in  the  best  possible 
working  order.  At  least  once  a  week  examine  and  carefully 
clean  the  lightning  arrester,  remove  all  oil  and  grease  from 
the  boxes,  and  carefully  clean  the  bearings.  Every  fortnight 
examine  the  armatures,  insulation,  and  fields;  repaint  and 
reshellac  them  if  necessary. 

The  trolleys  should  also  be  inspected,   and  all  bearings 


TIg  THE    ELECTRIC    RAILWAY. 

cleaned  and  properly  lubricated — especial  attention  being 
given  to  the  trolley  wheel.  There  should  be  good  contact 
between  the  wheel  and  "leading-down"  wires,  otherwise 
there  will  be  injurious  sparking  at  the  wheel.  The  trolley 
springs  should  be  adjusted  so  that  the  trolley  wheel  shall  be 
pressed  against  the  wire  firmly  enough  to  insure  a  good 
working  contact  when  running  at  full  speed. 

The  brake  mechanism  in  all  its  parts  should  be  thoroughly 
examined,  for  it  is  exceedingly  important  that  this  part  of 
the  apparatus  be  in  good  condition.  Cars  should  be  fur- 
nished with  good  sand  if  operated  on  hilly  roads. 

See  that  the  car  is  supplied  with  a  screwdriver,  monkey 
wrench,  etc.,  an  extra  lamp  or  two,  and  an  oil  lamp  for  use 
if  the  power  should  be  cut  off. 

B.  Operation  of  the  cars. 

'  i.  When  cars  are  left  standing  in  the  car  house  or  on  a 
side  track,  see  that  the  safety  or  cut-out  switches  are  placed 
so  that  the  circuit  is  open.  Generally  there  is  some  mark  on 
the  switch  to  show  the  proper  position  of  the  switch  lever. 
The  trolley  wheel  should  be  removed  from  the  wire  and  left 
in  such  a  position  as  to  relieve  the  trolley  springs  of  their 
tension. 

2.  Before  placing  the  trolley  wheel  on  the  wire,  be  sure  the 
circuit  is  open  at  the  switches,  and  before  closing  the  switches 
be  .sure  that  the  controller  handle  is  at  the  "off  "  stop. 

Before  placing  the  trolley  wheel  firmly  on  the  wire,  let 
the  side  of  the  wheel  just  touch  the  wire ;  if  any  flash  occurs, 
except  the  spark  which  may  be  seen  when  the  lamps  are  on, 
then  something  is  wrong,  and  the  wheel  should  be  kept  off 
the  wire.  Probably  a  switch  which  should  have  been  open 
will  be  found  closed. 

3-  If  there  is  a  reversing  switch  on  the  car,  see  that  it  is 
set  properly  before  applying  the  power. 

4-  Before  starting  the  car,  raise  the  traps  and  see  if  the 
commutators,    armatures,    gears,    etc.,   are   in    condition    for 
work.     See  that  the  brushes  and  holders  are  in  good  order 
and  properly  placed. 

5-  When  ready  to  start,  move  the  controller  handle  gradual- 
ly  but  firmly.     If  the  car  will  not  move,  throw  the  controller 


MOTORS    AND    CAR    EQUIPMENT.  119 

handle  off  and  look  at  the  several  switches  between  the  trolley 
wire  and  the  motors.  Probably  some  of  them  will  be  found 
open.  If  the  car  still  refuses  to  move,  throw  on  the  lamp 
circuit.  It  may  be  there  is  trouble  at  the  power  station, 
and  the  lamps  will  tell  the  story,  unless  it  happens  that  the 
dirt  on  the  track  prevents  a  contact  between  the  wheels  and 
the  rails.  If  this  is  the  case,  press  the  switch  stick  between 
the  rear  of  one  of  the  wheels  and  the  rail,  thus  securing  a 
ground.  On  many  roads,  an  insulated  wire  is  furnished  each 
car  for  use  in  just  such  cases  as  this. 

6.  Do  not  attempt  to  run  the  car  backward  unless  the  trol- 
ley is  closely  watched  by  some  one  who  holds  the  cord  in 
his  hand. 

7.  In  throwing  power  on,  move  the  controller  handle  step 
by  step,  allowing  the  car  to  gain  headway  under  one,  before 
advancing  to  the  next  step.     Too  sudden  starting  strains  the 
machinery  and  wrenches  the  gears,  etc. 

8.  In  throwing  the  power  off,  move  the  controller  handle 
gradually  until  nearly  at  the  "  off  "  stop,  when  it  should  be 
turned  the  rest  of  the  way  with  a  snap;    and  care  should 
be  taken  that  the  power  is  off  before  setting  the  brakes. 

9.  The  brakes  should  be  set  gradually,  so  as  not  to  bring 
an  undue  strain  upon  the  gearing. 

10.  Never  run  down  grade  faster  than  the  maximum  speed 
allowed  on  the  level,  and  always  keep  perfect  control  of  the 
car. 

1 1 .  If  the  trolley  jumps  off  the  wire,  a  slight  slowing  of  the 
car  may  be   felt,  and  at  night  the  lights  will  go  out ;  stop 
the  car  immediately,  after  throwing  the  controller  handle  to 
the  "off"  stop. 

1 2 .  When  by  accident  or  otherwise  the  current  from  the 
power  station    is    cut  off,   throw    the     controller    handle  to 
the  "  off  "'  stop,  throw  on  the  light  switch,  and  watch  for  the 
power.     When  the  power  is  on,  it  will  be  well  for  a  portion 
of  the  cars  only,   say  those  having  even  numbers,   to  start 
immediately,   the   others  waiting  a  minute  or  two.     If  all 
start  at  once,  a  severe  strain  may  be  placed  upon  the  dynamos 
and  engines. 

13.  Never  stop  a  car  on  a  curve,  except  in  case  of  accident. 


I2o  THE    ELECTRIC    RAILWAY. 

This  will  save  the  gearing  from  unnecessary  wear  and  tear, 
and  at  the  same  time  relieve  the  generators  and  motors  from 
excessive  strain  and  resulting  loss  of  power.  Many  break- 
downs and  troubles  have  resulted  from  unnecessarily  stopping 
on  curves.  The  extraordinary  amount  of  current  required 
to  start  a  loaded  car  on  a  curve  may  endanger  the  insulation 
of  the  motors. 

14.  Never  reverse  a  car  while  it  is  in  motion,  except  to 
avoid  serious  accident,  and  then  it  must  be  done  very  care- 
fully.    It  is  very  easy  to  overdo  the  matter,  blow  the  fuses, 
and  thus  perhaps  become  helpless  to  avert  some  second  ac- 
cident. 

15.  If  there  is  a  reversing  switch  on  the  car,  be  sure  that 
the  power  is  cut  off  before  throwing  the  switch. 

1 6.  In  any  case  of   reversal  to  avoid  accident,   turn  the 
reversed  power  on  very  gradually,  as  a  little  will  be  found 
sufficient  to  stop  the  car  quickly,  while  a  sudden  application 
of  the  power  might  strip  the  gears.     Break  the  current  as 
soon  as  the  car  stops. 

17.  Do  not  reverse  a  car  with  the  brakes  set,  for  the  fuse 
may  be  needlessly  blown. 

1 8.  Run  slowly  over  railroad  crossings,  curves,  switches, 
rough  track,  etc.     Remember  that  the  cars  are  heavy  and 
that  shaking  up  the  motors  should  be  avoided  as  much  as 
possible. 

19.  Run  through  water  very  slowly  and  carefully,  and  in 
examining  the  motors,  be  sure  that  no  water  drips  from  the 
clothing  or  elsewhere  upon  them.     Water  on  the  field  mag- 
nets will  soon  cause  them  to  burn  out. 

20.  Be  careful  that  nothing  falls  from  the  pockets  on  the 
motors,  and  do  not  let  any  metal— for  example,  an  oil  can- 
touch  the  brass  screws  on  the  connection  boards,  or  in  any 
way  cross-connect  parts  of  the  motor  circuit  unless  the  trolley 
is  off. 

2 1 .  Do  not  run  over  sticks,  stones,  or  wires ;  they  may  be 
caught  by  or  knocked  against  the  motors.     Remember  that 
the  motors  are  hung  very  low  and  are  apt  to  strike  such 
obstructions. 

22.  If  a  motor  is  flashing  badly  at  the  commutator,  or  gives 


MOTORS    AND    CAR    EQUIPMENT.  121 

out  a  burning  odor,  or  shows  weakness  in  any  way,  it  is  be&t 
to  cut  it  out.  Some  companies  provide  switches  to  do  this 
easily.  If  the  car  has  a  cut-out  switch,  insert  the  key  which 
should  be  with  it  in  the  socket,  with  pointer  up,  and  turn 
the  pointer  around  one-quarter  of  a  circle  toward  the  good 
motor.  Never  attempt  to  move  tliis  sivitc/i  unless  the  main  motor 
sivitc/i  is  off. 

23.  It  may  be  that  a  fuse  is  blown,   in  which  case  try 
another,  and  then  two  in  multiple,  which  will  generally  be 
sufficient  for  the  necessary  current  required  to  start  the  car. 

If  the  double  one  blows,  there  is  probably  a  serious  ground 
or  short-circuit,  which  needs  careful  attention. 

24.  Unless  very  familiar  with  their  current-carrying  capac- 
ity, never  put  copper  or  iron  wires  in  place  of  the  lead  fuse, 
for  it  is  the  function  of  this  fuse  to  "  blow  "  whenever  the 
motors  are  endangered,  and  if  a  wire  were  used,  perhaps  the 
current  which  it  would  allow  to  pass  would  damage  the  mo- 
tors seriously. 

25.  A  sure  way  to  stop  any  electrical  trouble  in  the  car  is 
to  remove  the  trolley  from  the  wire. 

26.  In  case  of  a  lightning  storm,  keep  cool,  for  there  is 
absolutely  no  danger ;  a  slight  noise  may  be  heard,  however. 
If  the  motors  are  damaged  by  lightning,  the  car  will  run 
unsteadily  or  stop  altogether.      If  lightning  damages   one 
motor,  cut  it  out.      If  both  are  damaged,   pull  the  trolley 
down  and  wait  to  be  pushed  back  to  the  car  house. 

27.  Never  run  down  grade  with  the  current  on;  but  the 
trolley  should  always  be  in  contact  with  the  wire  on  such 
occasions,  as  it  may  be  necessary  to  reverse  the  car. 

28.  Be  careful  in  the  use  of  sand  on  the  track,  as  too  much 
will  prevent  good  ground  connections.     A  very  small  amount 
will  serve  to  keep  the  wheels  from  slipping. 

29.  The  power  should  be  shut  off  when  passing  a  "trolley 
break"  or  "section  insulator." 

30.  In  ordinary  stopping  of  a  car,  always  release  the  brake, 
but  do  not  let  it  fly  just  before  coming  to  a  dead  stop.     The 
armature  will  then  be  able  to  gather  up  the  lost  motion  in 
the  gears  and  shafting,  and  will  be  ready  for  a  smooth  start. 

31.  Do  not  attempt  to  make  up  time  on  grades  or  rough 


I22  THE    ELECTRIC    RAILWAY. 

tracks;  in  fact,  never,  at  the  expense  of  the  machinery,  try  to 
make  up  lost  time. 

32.  Supposing  the  car  to  be  equipped  with  Sprague-Edison 
apparatus  (commutated  fields),  the  following  rules  regarding 
the  use  of  the  switch  box  will  be  found  helpful :   Never  dally 
in  the  movement  of  the  handle.     Move  on  slowly  from  step 
to  step,  allowing  the  car  to  respond  to  each  step  and  gather 
headway  before  proceeding  to  the  next  step.     In  case  the 
switch  turns  hard,  move  the  pointer  to  the  notch  by  a  suc- 
cession of  slight  taps;    this  will  prevent  running  over  the 
notch. 

In  case  you  do  run  over  the  notch  one-third,  when  throw- 
ing on  power,  move  on  to  the  next  notch.  In  throwing  off 
power,  pass  the  fourth  notch  quickly.  In  case  (in  throwing 
off)  you  run  over  one-third  of  a  space,  go  back  to  the  last 
one  passed. 

The  best  notches  in  throwing  off  are  from  five  to  three 
and  from  three  "off."  Throw  the  pointer  from  the  first 
notch  to  "  off  "  with  a  snap.  When  leaving  the  switch,  even 
for  a  moment,  take  the  handle  off  and  leave  it  in  the  car. 
Always  allow  the  car  to  gain  speed  at  one  notch  before  giv- 
ing it  another.  Never  throw  the  switch  on  the  fifth  notch 
if  the  car  does  not  start  on  the  preceding  ones.  Never  ap- 
ply the  brakes  when  the  switch  is  turned  on. 

When  necessary  to  go  beyond  the  fourth  notch,  pass  slowly 
to  the  seventh,  never  stopping  on  the  fifth  or  sixth:  and 
always  use  the  seventh  notch  on  grades.  Of  the  lower 
notches,  the  third  should  be  used  in  preference  to  the  first, 
second,  or  fourth.  Prepare  for  heavy  grades  by  throwing 
the  switch  on  to  the  fifth  and  the  last  notch,  when  the  car 
is  going  its  fastest  at  the  foot  of  the  grade.  During  wet 
weather,  however,  if  the  car  wheels  slip  while  on  the  grade, 
work  the  switch  back  to  the  fourth  point,  or  even  work  it 
back  to  the  first  point  and  "off  "  point,  until  the  wheels  get  a 
gripe,  then  work  up  gradually  to  the  seventh  notch. 

33.  Familiarize  yourself  with  the  peculiar  noises  made  by 
the  apparatus,    in   order  that  you   may  detect  in   this   way 
whether  the  motors  are  acting  properly. 


CHAPTER   IV. 

THE    LINE. 

OF  an  electric  railway,  the  conducting  system,  as  a  whole, 
has  come  to  be  known  simply  as  "the  line." 

It  may  be  considered :  (A)  Merely  as  a  conductor.  Tak- 
ing this  view  of  it,  the  proper  material,  its  resistance,  cross- 
section,  and  weight  are  the  points  to  be  determined. 
Copper  is  now,  and  will  continue  to  be,  the  cheapest  con- 
ducting metal,  so  long  as  there  shall  be  maintained,  even 
approximately,  the  present  relations  between  the  specific 
resistances  and  prices  of  the  various  metals.  (B)  As  a  con- 
ductor in  place,  insulated  more  or  less  highly,  and  supplying 
current  in  a  suitable  manner  to  a  number  of  cars. 

Before  calculations  as  to  the  line  resistance  can  be  made, 
it  is  evident  that  the  following  conditions  must  be  known : 
(i)  The  initial  pressure,  i.e.,  the  voltage  at  the  station ;  (2) 
the  average  or  the  maximum  demand  for  current;  (3)  the 
allowable  "  drop  "  on  the  line  at  the  average  or  maximum 
load;  (4)  the  average  distance  over  which  the  current  at 
the  average  or  the  maximum  load  is  to  be  transmitted. 

I.  Railway  dynamos  are  now  quite  generally  run  at  a 
difference  of  potential,  between  the  brushes,  of  500  volts. 
This  value  may  fairly  be  considered  as  a  compromise  between 
considerations  of  economy  in  copper  on  the  one  hand,  and 
safety  to  life  and  facility  of  insulation  on  the  other.  The 
question  of  danger  to  life  has  been  thoroughly  and  frequently 
discussed  in  public  hearings  before  municipal  authorities.  It 
.seems  that  nothing  need  here  be  said  further  than  this,  that 
as  yet  no  human  being  has  either  been  killed  or  seriously 
injured  by  the  shock  due  to  a  500- volt  continuous  current; 
though,  of  course,  many  persons  while  handling  electric 
apparatus  have  received  such  shocks.  Several  horses  have 
been  killed  by  railway  wires,  while  in  other  cases  special 
efforts  to  kill  a  horse  in  this  way  have  failed. 

123 


I24  THE    ELECTRIC    RAILWAY. 

In  the  direction  of  insulation  against  loss  of  current,  prac- 
tically nothing  remains  to  be  accomplished.  A  higher  press- 
ure than  500  volts  could  be  satisfactorily  insulated,  so  far  as 
loss  of  current  is  concerned;  but  the  fear  of  danger  to  life, 
in  all  systems  requiring  in  any  way  the  use  of  bare  wires  in 
exposed  situations,  will  doubtless  keep  the  service  pressure 
for  railways  on  the  city  streets  where  it  now  is,  from  500  to 
600  volts. 

2.  The  predetermination  of  the  average  or  maximum  load 
cannot  be  made  with  exactness.  Given  a  certain  schedule  to 
be  observed  by  a  given  number  of  cars,  the  power  required 
to  perform  that  service  varies  with  the  condition  of  the  track 
and  the  running  gear,  the  efficiency  of  the  motors  used,  the 
skill  of  the  motorman,  the  weight  of  the  cars  and  passengers, 
the  magnitude  of  the  grades  and  curves,  the  number  of  stops, 
and  the  relation  between  the  number  of  cars  simultaneously 
ascending  and  descending  grades.  And  again,  even  if  all 
these  variables  may  be  given  particular  values  for  a  given 
schedule,  we  must  recognize  the  fact  that  quite  frequently 
the  schedule  itself  is  not  maintained.  In  spite,  however,  of 
these  uncertainties,  it  has  been  possible  to  adopt  rules  which 
are  fairly  satisfactory  guides  in  the  calculation  of  the  copper 
required.  When  the  service  to  be  performed  over  given  lines 
is  known  in  a  general  way,  we  should  then  seek  to  define 
(a)  the  maximum  number  of  cars  that  may  be  simultaneously 
on  the  line ;  (b)  the  number  that  may  be  ascending  known 
grades  and  the  speeds  required ;  (c)  the  number  descending 
grades  on  which  gravity  is  sufficient  to  propel  them ;  (d)  the 
number  on  levels  and  the  speed  required;  (e)  the  weights 
(live  or  dead)  to  be  carried;  (f)  the  horizontal  effort  in 
pounds  required  to  propel  a  given  weight,  say  one  ton,  over 
tracks  such  as  may  be  in  question.  This  last  is  known  as 
the  traction  co-efficient.  Given  the  above  values,  we  may 
easily  calculate  the  whole  work  to  be  done,  and  may  express 
it  in  terms  of  horse-power,  or  finally,  in  terms  of  current 
and  E.  M.  F. 

Thus,  let  us  suppose  twenty-five  cars  on  the  line,  of  which 
ten  are  ascending  grades  averaging  five  per  cent.,  and  at  the 
rate  of  five  miles  per  hour;  ten  are  moving  down  grades, 


THE    LINE.  125 

requiring  no  current;  five  are  on  the  levels,  making  ten 
miles  per  hour.  We  will  suppose  each  car  and  its  motors  to 
weigh  10,000  pounds,  and  the  passengers  of  each  car  to  weigh 
also  10,000  pounds.  The  work  to  be  done  is  of  two  kinds: 
first,  that  against  gravity;  second,  that  against  the  friction 
of  the  running  gear.  Atmospheric  resistance  at  street-car 
speeds  is  small,  and  may  be  neglected,  or  considered  as 
combined  with  that  of  friction.  The  work  done  against 
gravity  is  thus  calculated:  Weight  lifted  =  10  (cars)  X 
20,000  pounds  =  200,000  pounds. 

Height  of  lift  per  minute  equals  the  rise  per  foot  on  the 
grade»(o.05  feet)  multiplied  by  the  number  of  feet  traveled 
per  minute.  Now,  five  miles  per  hour  is  equivalent  to  440 
feet  per  minute ;  hence  the  total  rise  per  minute  will  be 
440  X  0.05  =  22.00  feet. 

The  work  done  against  gravity  per  minute  will  be,  then, 
200,000  X  22  =  4,400,000  foot-pounds,  a  rate  of  133.3  horse- 
power. 

For  the  track  in  question,  let  us  assume  that  a  horizontal 
effort  of  30  pounds  per  ton  will  overcome  friction.  (This  is 
a  safe  outside  figure  for  all  ordinary  tram-rail  track.)  Then, 
for  the  10  cars,  we  have  100  (tons)  X  30  ( pounds)  X  440  feet 
per  min.  =  1,320,000  foot-pounds  per  min.,  a  rate  of  40  horse- 
power; also  for  the  five  cars  on  the  levels,  we  have  50  X  30  X 
•880  feet  per  min.  =  1,320,000  foot-pounds  per  min.,  a  rate  of 
40  horse-power.  Thus,  for  keeping  all  the  cars  in  motion, 
we  need,  133  +  40  +4°  =  213  horse-power. 

This  power,  however,  is  that  actually  needed  at  the  axles, 
while  that  delivered  to  the  motors  must  include  all  losses 
in  the  motors  and  gearing.  Suppose  this  to  be  25  per 
cent,  of  the  power  delivered  to  the  cars.  Therefore,  we 
must  supply  213  ^0.75  =2 84  horse-power.  Since  we  premise 
that  the  pressure  under  which  the  current  flows  is  about  500 
volts,  and  since  746  watts  =  i  horse-power,  we  may,  with 
sufficient  accuracy,  say  that  1.5  amperes  on  the  line  will  be 
equivalent  to  i.o  horse-power.  Then,  for  the  total  current 
we  shall  have  284  X  i  •  5  =  426  amperes.  In  this  detailed  way 
the  power  required  may  be  calculated.  But  it  is  usually 
sufficient  to  allow  without  such  detail  10  to  15  horse-power 


126  THE    ELECTRIC    RAILWAY. 

as  the  maximum  per  car  for  service  over  considerable  grades 
and  in  case  the  total  number  of  cars  is  in  the  neighborhood 
of  20.  This  is  quite  sufficient  for  1 6-foot  cars.  For  roads 
having  practically  no  grades,  and  for  a  large  number  of  cars, 
the  allowance  may  be  as  low  as  7  or  8  horse-power  per  car. 

3.  As  to  the  allowable  "  drop  "  of  potential,  it  is  determined 
principally  by  the  requirement  of  a  close  uniformity  of  con- 
dition, in  order  that  the  same  motors,  moving  all  along  the 
line,  shall  be  able  to  give  practically  uniform  results  at  all 
points.  It  has  been  found  that  a  variation  of  10  to  15  per 
cent,  from  the  station  to  the  point  of  lowest  potential  will 
not  injuriously  affect  the  speed  demanded  of  the  motors. 

In  making  the  following  calculations  for  the  copper  to  be 
used,  we  must  have  clearly  in  mind  just  what  conditions  we 
wish  to  produce.  There  has  been  a  great  deal  of  loose 
thought  and  loose  calculation  in  the  matter.  Thus,  have  we 
in  view  simply  a  fixed  maximum  "drop"  of  say  100  volts? 
This  may  seem  a  definite  condition,  fixing  the  copper  accu- 
rately, yet  it  is  not  enough,  save  in  very  simple  cases,  to 
insure  uniformity  in  the  determinations  by  different  engi- 
neers, even  though  they  make  the  same  assumptions  concern- 
ing the  value  of  the  rail  return.  By  one  of  them  the  line 
may  be  wired  in  such  fashion  that  the  maximum  drop  should 
occur  at  many  places  under  many  conditions,  while  by  an- 
other it  may  be  so  wired  that  the  maximum  drop  could 
occur  only  in  a  few  places  and  under  few  conditions.  The 
weight  of  copper  in  the  first  case  would  be  considerably  less 
than  in  the  second. 

Again,  have  we  in  view  a  certain  average  drop,  say  fifty 
volts?  This  in  turn,  standing  alone,  is  not  definite  enough; 
for  we  must  ask  whether  we  shall  consider  the  average  drop 
to  be  determined  under  a  fixed  maximum  load  (expressed  in 
amperes  or  horse-power),  or  when  a  fixed  number  of  cars  is 
in  ordinary  service;  and  further,  shall  this  average  be  deter- 
mined from  readings  taken  on  one  car  while  running  over 
all  the  line  or  lines,  or  shall  it  be  determined  by  readings 
taken  on  all  the  cars  at  the  same  instant,  or  shall  the  average 
readings  of  a  round  trip  on  each  of  many  lines  be  required 
to  fall  within  the  fixed  limit?  Further,  if  we  aim  at  an 


THE    LINE.  127 

average  loss  as  the  determining  condition,  we  must  still  have 
in  view  some  limiting  maximum  drop,  otherwise  the  condi- 
tions concerning  the  average  drop  might  be  obtained,  while 
the  resulting  service  might  be  poor  indeed. 

If  the  copper  placed  on  the  line  has  a  uniform  cross- 
section  along  the  whole  length,  then  the  observance  of  any 
given  condition  as  to  average  drop  will  carry  with  it  a  fixed 
maximum  drop,  and  vice  versa.  This  is  because,  with  a 
imiform  cross-section  and,  as  is  usually  the  case,  a  tolerably 
uniform  distribution  of  load  along  the  line,  there  must  neces- 
sarily be  an  approximately  regular  drop  of  potential  from 
the  station  to  the  farthest  point  at  which  service  is  performed. 
If,  however,  the  line  be  broken  into  many  sections,  each 
supplied  with  current  separately,  this  necessary  relation  be- 
tween the  maximum  and  average  drop  ceases  to  exist.  Thus, 
let  us  suppose  the  governing  condition  to  be  that  the  average 
pressure  on  the  line  when  cars  are  in  regular  service  shall  be 
400  volts.  Let  us  further  suppose  the  line  to  be  divided 
into  four  separately  fed  sections.  On  one  of  these,  the  aver- 
age pressure  might  be  300  volts,  while  on  the  other  three  it 
might  be  433  volts,  the  average  for  the  whole  line  still 
remaining  at  400  volts ,  yet  this  would  certainly  not  be  the 
condition  aimed  at  by  good  engineering,  since  it  is  not  desir- 
able that  the  pressure  should  on  any  section  be  so  low  as 
300  volts.  Generally  speaking,  indeed,  this  may  be  said: 
that  the  more  complex  the  wiring,  the  more  necessary  is  it 
accurately  to  define  the  conditions  desired,  in  order  that  like 
results  shall  be  reached  by  different  calculators.  This  whole 
matter  is  of  constantly  increasing  importance,  since  there  is, 
especially  on  the  larger  systems  of  railways,  an  increasing 
tendency  toward  the  subdivision  of  the  lines  into  separately 
fed  sections. 

A  very  reasonable  specification,  and  one  of  wide  applica- 
tion, may  be  thus  expressed — namely:  on  any  section  the 
average  pressure  shall  not  be  less  than  450  volts,  and  the 
minimum  pressure  shall  not  be  less  than  400  volts.  This 
rule  will  apply  as  well  to  the  case  in  which  the  whole  line  is 
electrically  continuous  as  to  the  case  of  subdivision,  since 
the  whole  line  in  the  case  supposed  would  constitute,  in  the 


I28  THE   ELECTRIC    RAILWAY. 

sense  in  which  the  word  is  here  used,  one  section.  It  should 
further  be  specified,  that  the  average  and  minimum  pressure 
above  mentioned  should  be  found  under  conditions  of  maxi- 
mum load  for  regular  traffic.  Reasonable  discretion  must  be 
used  in  determining  for  any  such  case  what  shall  be  called 
regular  traffic. 

It  would  perhaps  be  increasing  unnecessarily  the  amount 
of  copper  required,  to  insist  that  the  given  pressure  should 
be  found  in  case  of  maximum  extraordinary  load;  as,  for 
instance,  when  snow  covers  the  tracks,  increasing  the  power 
required  for  the  propulsion  of  the  cars  in  service,  and  usually 
also  causing  an  extraordinary  demand  for  current  to  operate 
snow  plows  and  snow  sweepers. 

4.  Having  in  view  these  specifications,  we  may  next  con- 
sider the  distribution  of  the  copper  which  is  to  be  put  up  in 
the  line.  The  following  cases  arise  in  practice: 

CASE  I.  (Fig.  69). — A  single  bare  conductor,  the  trolley 
wire,  usually  of  uniform  diameter  throughout  its  length,  is 
used  to  convey  all  the  current  required  for  the  car  service 
over  a  given  line  (or  section  of  line).  Only  in  case  of  a  com- 
paratively small  number  of  cars  and  a  comparatively  short 
line  can  this  method  be  economically  used.  The  line  pressure 
in  such  case  must  always  be  found  continuously  lower  from 


FIG.  69. 

the  station  to  the  farthest  point  of  service.     No  two  points  on 
such  a  line  could  have  equal  pressure. 

This  first  condition,  geometrically  illustrated,  may  be  rep- 
resented by  a  straight  line  of  uniform  thickness,  as  A  B  (Fig. 
70) ,  in  which,  let  A  represent  the  position  of  the  station.  Over 
any  section  measured  from  A  toward  B  must  pass,  not  only 
the  current  required  by  the  cars  on  that  section,  but  also  the 
current  for  all  the  sections  beyond.  If,  therefore,  the  resist- 
ance in  the  section  A  D  be  just  equal  to  that  in  the  section 
F  B,  the  drop  in  voltage  along  the  first  section  would  be 
greater  than  along  the  second,  and  still  greater  than  along 
the  third  and  fourth.  Thus,  if  the  tangent  of  the  angle 


THE    LINE. 


129 


A  E  C  represents  the  whole  current  supplied  to  the  cars,  and 
if  we  now  take  A  B  as  representing  the  total  and  A  E  the 
average  resistance  over  which  the  total  current  must  flow, 
then  the  vertical  line  A  C  may  be  taken  as  representing  the 
50  volts  total  "drop,"  bearing  in  mind  the  geometrical  rela- 
tion that  the  tangent  of  the  angle,  A  E  C,  varies  with  the 

AC  E 

ratio  -T-™  analogous  to  the  expression  of  Ohm's  law  C  =^>  . 
A.  iii  -K. 

Following  this  geometrical    method,   draw  through  m1  a 
line  to  A  C,  making  the  tangent  of  the  angle  at  m1  equal  to 


one-fourth  that  at  A  EC.  This  tangent  will  correspond  to 
the  current  required  for  the  first  section  flowing  over  the 
resistance  A  D  -^  2,  and  the  vertical  line  A  H  will  represent 
the  "  drop  "  over  the  first  section  for  its  otvn  service,  and  will 
be  one-sixteenth  of  the  total  "drop, "or,  in  specific  value, 
3.125  volts.  (The  fact  that  the  load  of  each  section  is  pre- 
sumably distributed  along  its  whole  length,  instead  of  being 
concentrated  at  one  end,  renders  this  illustration  inexact, 
but  none  the  less  valuable  as  setting  forth  the  principle.) 

Through  m"  draw  the  line  to  J  m\  making  an  angle  with 
A  B  oqual  to  H  m1  A.  Then  A  J  will  represent  the  number 
of  volts  required  to  force  the  current  for  the  second  section 
over  the  resistance  A  E.  Draw  other  oblique  lines  at  m3 
and  at  m4,  parallel  to  the  lines  through  m1  and  m",  and  like- 
wise intersecting  A  C.  Then  draw  vertical  lines  through 
D,  E,  and  F,  intersecting  the  oblique  lines.  The  total  fall 
of  potential  over  the  first  section  is  now  seen  to  be  A  H  for 
its  own  load,  H  J  for  the  load  of  the  second  section,  J  K  for 
9 


j,0  THE    ELECTRIC    RAILWAY. 

that  of  the  third  section,  and  K  L  for  that  of  the  fourth  sec- 
tion—each of  these  latter  quantities  being  two-sixteenths  of 
the  total,  or  twice  as  great  as  the  quantity  required  for  the 
first  section  itself.  This  is  because  the  current  of  the  second, 
third,  and  fourth  sections  must  be  carried  over  the  whole 
length  of  A  D,  while  its  own  current  is  carried  over  an  aver- 
age distance  of  A  m1,  only  one-half  of  A  D.  Of  the  total 
"drop  "  it  appears,  then,  that  TV  +  (A  X  3)  =  T'G  takes  Place 
on  the  first  quarter  of  the  total  distance.  On  the  second  sec- 
tion, the  "drop"  in  like  manner  is  found  to  be  f5g  ;  on  the 
third,  fV;  on  the  fourth,  -fa.  The  actual  pressures  in  specific 
values  would  be  at  A,  500  volts;  at  D,  500 — (T7g  X  5°)  = 
478.2:  at  E,  478. 2  —  (T'V  X  50)  =462. 6;  atF,  462.6— (T3g-X 
50)  =  453-2;  at  B,  450.0. 

While  the  "  drop  "  when  referred  to  equal  sections  of  the 
whole  line  is  thus  seen  to  be  irregular,  this  condition  is  not 
generally  to  be  considered  objectionable. 

CASE  II. — A  continuous  trolley  wire,  uniform  in  diameter, 
is  connectc  1  »t:  intervals  of,  say,  from  500  to  1,000  feet  to 
a  continuous  feeder  wire,  also  of  uniform  diameter.  If,  in 
any  case,  more  than  one  feeder  should  be  connected  at  inter- 
vals to  the  same  section  of  trolley  wire,  the  case  would  still 
be  analogous  to  the  simpler  one  above,  since  in  both  there 
is,  over  the  distance  in  question,  a  uniform  total  cross-section 
of  copper,  over  which  the  current  passes  for  the  car  service. 
This  method  will  be  understood  by  reference  to  the  diagram, 


P.S, 


i    i    i    i    i    i   i: 


FIG.  71. 

Fig.  71.  S  T  represents  the  trolley  wire ;  F  F  '  the  feeder  (or 
feeders)  connected  to  the  trolley  wire  at  relatively  short  inter- 
vals, perhaps  every  500  feet.  In  this  case,  the  trolley  wire 
may  be  of  small  diameter,  since  the  maximum  current  over 
any  of  its  parts  is  only  that  required  for  the  service  done  in 
about  2 50  feet — that  is,  half  the  interval  between  sub-feeders, 
A,  B,  and  K.  A  car  placed  at  D,  midway  between  A  E  and 
I.  C,  would  receive  a  part  of  its  current  from  A  E  (the  sub- 


THE    LINE.  131 

feeder  nearer  the  station)  and  part  along  the  feeder  F  F  ', 
through  B  C  and  the  trolley  wire  back  to  D,  the  proportions 
being  in  inverse  ratio  to  the  resistances  of  the  two  paths 
divergent  at  A.  Another  portion  would  flow  directly  from 
the  station  along  the  trolley  wire. 

In  practice,  the  trolley  wire  used  in  this  system  of  com- 
paratively numerous  sub-feeders  has  varied  in  size  from  No. 
6  B.  &  S.  to  No  o.  In  the  system  first  described,  the  trol- 
ley wire,  having  to  carry  the  whole  current  a  greater  dis- 
tance, has  rarely  been  less  than  No.  o,  and  has  been  as  large 
.as  No.  oo  B.  &  S. 

CASE  III. — A  trolley  wire,  of  uniform  cross-section,  is 
broken  into  short  lengths  insulated  from  each  other,  each 
length  being  connected  at  one  point  to  the  feeder,  one  feeder 
thus  supplying  the  current  for  a  considerable  number  of 
trolley-wire  sections.  This  is  analogous  to  the  second  case 
just  considered,  except  that  the  conductivity  of  the  trolley 
wire  itself  is  of  service  only  over  the  distance  from  each  sub- 
feeder  to  the  end  of  that  particular  trolley- wire  section. 

For  a  car.  at  B,  Fig.  72,  the  whole  current  required  must 


E  B       C       B'  H 

FIG.  72. 

pass  over  the  feeder  A,  thence  along  a  sub-feeder  to  C, 
thence  to  B  or  B  '.  Now,  although  the  current  cannot  come 
over  the  trolley- wire  sections  between  the  station  and  B,  yet, 
as  in  the  two  preceding  cases,  the  "  drop  "  of  line  pressure  is 
•continuous  from  section  to  section  of  the  trolley  wire,  since 
the  pressure  on  this  wire  must  be  determined  by  that  of  the 
feeders  at  the  points  of  junction  with  the  trolley- wire  sec- 
tions. The  car  at  B,  however,  must  be  working  under  a 
lower  pressure  than  the  car  at  B',  if  the  load  from  C  to  B  is 
greater  than  from  C  to  B';  but  a  car  at  E  must  always  be 
working  under  a  higher  pressure  than  a  car  at  C,  and  so  on, 
from  section  to  section. 

This  subdivision  into  short  and  independent  trolley-wire 
sections  has  been  required  in  certain  cases,  as  a  safeguard  in 


!„-,  THE   ELECTRIC    RAILWAY.' 

case  of  fires  along  the  line.  Each  of  these  independent  sec- 
tions may  be  supplied  with  a  switch,  conveniently  placed  on 
one  of  the  supporting  poles ;  and  the  operation  of  this  switch, 
placed  at  K  in  the  sub-feeder  connecting  the  trolley  wire 
with  the  feeder  wire  proper,  enables  the  trolley  wire  to  be 
thrown  in  or  out  of  circuit  at  will.  A  fusible  plug  may 
readily  be  placed  in  the  same  box  containing  the  switch,  and 
any  short  circuit  of  this  particular  line  section  may  thus  be 
made  automatically  to  cut  the  section  out  of  service. 

The  same  remarks  concerning  the  feasibility  of  cutting  out 
these  independent  trolley  sections  (either  at  will,  by  the 
switch,  or  automatically  by  the  fusible  plug)  that  apply  in  this 
case  (III.)  apply  in  case  V.,  as  will  be  seen  when  the  latter  is 
discussed. 

CASE  IV. A  continuous  trolley  wire  of  uniform  diameter 

is  fed  .at  intervals  by  independent  feeders,  each  running 
direct  from  the  station.  It  is  plain  that  each  of  these 
feeders  may  be  so  calculated  as  to  give,  under  assumed  con- 
ditions of  load,  equal  line  pressures  at  the  points  of  junction 


(A,  B,.C,  D,  and  H)  with  the  trolley  wire,  Fig.  73.  Then  a 
car  at  E  would  receive  its  supply  of  current  partly  from  A 
and  partly  from  the  point  B,  and  these  parts  of  the  current 
supply  would  be  dependent  upon  the  distances  of  the  car 
from  the  points  A  and  B,  respectively,  and  in  inverse  ratio  to 
these  distances.  It  is,  of  course,  not  convenient  to  run  a 
very  large  number  of  separate  feeder  wires.  The  trolley 
wire,  therefore,  is  usually  fed  at  a  comparatively  small  num- 
ber of  points,  and  consequently  the  distance  over  which  the 
current  is  conveyed  on  the  trolley  wire  alone  is  much  greater 
than  in  cases  II.  and  III.  The  size  of  the  latter  has,  there- 
fore, usually  been  greater,  the  most  general  practice  having 
been  to  use  a  No.  o  copper  wire,  with  a  distance  between 


THE    LINE. 


133 


feeding  points  varying  from  1,000  to  10,000  feet.  Care 
should  be  taken,  in  using  this  method,  so  to  limit  the  length 
of  the  intervals  that  a  trolley  wire  of  convenient  size  shall 
not  be  required  to  carry  a  current  which,  over  the  fixed 
resistance,  will  produce  an  excessive  "drop." 

A  variation  of  this  case  consists  in  connecting  two  or  more 
of  the  feeders  together  at  the  point  of  junction  of  any  one  of 
them  with  the  trolley  wire.  Thus,  at  F  the  four  feeders 
may  be  made  practically  into  one  conductor,  the  four  being 
themselves  in  multiple  with  the  trolley  wire,  which  is  sup- 
posed to  have  at  a  point  very  near  the  station  a  short  connec- 
tion to  the  dynamos.  The  effect  of  such  a  connection  as  that 
indicated  at  F  will,  of  course,  be  to  lower  the  pressure  pro- 
duced at  B,  C,  and  E,  with  the  three  longer  feeders  entirely 
independent  each  of  the  other;  but  such  a  cross-connection 
maybe  advisable  if,  after  beginning  operation,  the  load  at  any 
point,  as  at  A,  is  found  to  be  much  heavier  than  was  orig- 
inally assumed. 

CASE  V. — The  trolley  wire  is.broken  into  sections  insulated 
from  each  other  (Fig.  74),  each  section  being  supplied  by  one 


or  more  feeders  not  connected  with  the  other  sections.  As  in 
case  IV.,  the  potentials  at  A,  B,  C,  D,  and  H  may  be  made 
equal;  and,  as  in  case  III.,  the  conductivity  of  the  trolley  wire 
for  service  is  lost,  except  as  it  serves  to  convey  current  from 
the  points  of  junction  with  the  feeders  to  the  car  in  any  partic- 
ular part  of  a  particular  section.  The  current  for  all  the  cars 
that  may  be  found  in  any  one  section  must  be  carried  wholly 
over  the  feeder  or  feeders  of  that  section,  the  feeders  and 
trolley  wire  of  other  sections  being  electrically  independent 
each  of  the  other.  It  has  been  usual  to  make  the  trolley 
wire  for  this  case  of  about  the  same  size  as  that  for  case  IV. , 
namely:  No.  o  B.  &  S 


J34  THE    ELECTRIC    RAILWAY. 

The  great  advantage  obtained  by  this  system  lies  in  this, 
that  the  effects  of  several  classes  of  accidents  on  the  line  may 
thus  be  localized,  and  each  feeder,  being  supplied  with  a 
break  switch  in  the  station,  may  thus  be  thrown  in  or  out  of 
circuit  at  will,  the  other  trolley  sections  not  being  in  any 
way  affected  thereby.  If,  then,  the  trolley  wire  be  broken  at 
any  point,  or  if  there  be  a  short  circuit  to  ground,  the  move- 
ment of  the  cars  over  the  other  sections  need  not  be 
interrupted. 

In  any  of  the  cases  discussed,  it  is  frequently  possible  to 
carry  the  cars  across  the  break  by  the  headway  gained  before 
reaching  it.  If,  however,  there  be  but  one  feeder  connection 
to  any  trolley- wire  section  (not  itself  connected  to  the  station) , 
and  if  the  break  should  occur  between  this  feeder  connection 
and  any  cars  in  question,  as  when  the  break  is  at  L  and  the 
car  at  N,  Figs.  72  and  74,  the  car  would  be  deprived  of 
power  to  obtain  the  necessary  headway,  unless  the  break 
should  be  so  near  the  adjoining  trolley  section  that  the  car 
could  run  by  its  headway  from  that  adjoining  section  across 
the  insulating  joint  between  the  trolley  wires,  and  also  across 
the  accidental  break. 

With  respect  to  this  matter  of  the  ability  to  run  across  a 
break  in  the  trolley  wire,  cases  II.  and  IV.,  Figs.  71  and  73, 
show  an  advantage.  In  either  of  these  cases,  a  car  is  able  to 
receive  current  either  from  its  rear  or  from  its  front,  accord- 
ing as  the  break  is  in  front  of  or  behind  it. 

CASE  VI. — This  consists  of  a  combination  of  either  IV.  or 
V.  with  III.  It  is  of  great  value  on  lines  having  very  heavy 
traffic.  The  trolley  wire  alone,  when  of  convenient  size  to 
handle,  is  (for  heavy  traffic)  not  able  to  supply,  without  too 
great  loss,  the  current  required  by  sections  (between  feeding- 
in  points)  of  such  length  as  would  be  needed  in  order  to 
keep  the  number  of  independent  feeders  within  reasonable 
limits.  The  remedy  is  plainly  to  place  between  the  feeders, 
at  their  point  of  junction,  copper  in  excess  of  that  found  in 
the  trolley  wire.  Such  a  connecting  conductor  is  called  a 
mam.  It  is  connected  at  two  or  more  points  with  the  trolley 
wire.  This  combination  must  recommend  itself  in  all  large 
systems  of  electric  street  railways. 


THE    LINE.  135 

Let  us  next  determine  for  the  cases  above  described  the 
area  and,  consequently,  the  resistance  of  the  conductors  that 
will  be  necessary  to  carry  the  required  current  to  the  cars 
under  the  conditions  given. 

We  will  assume,  for  simplicity,  that  we  have  10  cars  uni- 
formly distributed  over  a  distance  of  2  miles ;  that  each  one 
of  these  cars  requires  a  current  of  1 5  amperes,  which,  at  450 
volts,  is  nearly  equivalent  to  10  horse-power. 

E                 E        Volts  lost 
From  Ohm  slaw,  C  =  -^-  (i),  or-~-  = ~ =  R     (2) 

The  resistance  of  any  wire  is 

length  in  feet  X   10.8 
area  in  circular  mils  ' 

10.8    ohms   being  the    resistance    of  a   wire    of  length   one 
foot  and  diameter  .001  of  an  inch. 
Equating  (2)  and  (3),  we  have — 

Volts  lost       length  in  feet  X  10.8 

C  area  in  c.  m. 

and  by  transposing  we  get — 

length  in  feet  X  10.8  X  C 
c.  m.  =  —        — ;^T — = —  (O 

\  olts  lost 

From  this  formula,  which  holds  for  any  metallic  circuit, 
we  may  readily  find  the  area  necessary  for  any  required  cur- 
rent, with  any  desired  per  cent,  of  "  drop,"  when  the  distance 
of  transmission  is  known. 

Let  us  now,  for  simplicity,  further  assume  in  these  calcu- 
lations that  the  resistance  of  the  return  circuit  is  nil.  This 
puts  all  the  resistance  into  the  overhead  line  or  lines,  or,  in 
other  words,  reduces  the  area  of  the  wires  to  one-half  of  what 
it  would  be  if  the  circuit  were  a  double  metallic  circuit,  each 
side  having  the  same  resistance ;  or,  briefly,  we  may  consider 
only  the  distance  out  one  way,  not  the  return. 

The  irregularity  of  the  "drop,"  when  referred  to  sections 
of  equal  length  and  resistance,  has  been  shown  in  the  geo- 
metrical treatment  of  case  I.  We  can,  however,  obtain  a 
general  expression  determining  the  distribution  of  "  drop" 
as  between  any  assumed  divisions  of  a  continuous  wire  of 
uniform  size.  We  may  represent  the  ten  cars  as  regularly 
placed  along  the  line  in  Fig.  71. 


136  THE   ELECTRIC    RAILWAY. 

The  distance  from  the  station  to  No.  i  is  1,056  feet,  and 
that  is  the  distance  between  successive  cars. 

Let  C  be  the  average  current  required  by  each  car  ;  for  the 
general  case  illustrated  above,  the  number  of  cars  by  N,  the 
interval  by  d,  the  resistance  of  d  by  R.  The  total  current 
from  the  station  will  be  N  C,  from  the  station  to  the  first  car 
the  "  drop"  will  be  N  C  R,  from  the  first  car  to  the  second 
(N-i)  C  R,  from  second  to  third  car  (N-2)  C  R,  etc.,  the 
"drop"  over  the  last  section  being  C  R.  The  total  "drop," 
which  we  may  represent  by  E,  is  made  up  of  the  sum  of 
these  quantities  or  may  be  expressed  : 

E  =  CR(N+(N-i)+  (N-2)+          +         )          (6). 

The  sum  of  the  series  in  parentheses  we  know  from  alge- 
braic demonstrations  to  be  represented  by  the  expression, 


We  then  have  E  =  C  R  —          -   (7)  ;      for    the    resistance 

2  E 
of  any  section,  R  = 


Now  let  us  consider  any  section  whatever,  as  that  which 
is  in  sections  distant  from  the  station.  The  current  flowing 
over  this  section  will  be  represented  by  C  (N  —  m).  The 
"volts  lost"  will  be  C  (N  —  m)  R.  In  equation  (8)  we  have 
the  value  of  R,  true  for  all  sections.  Substitute  this  value 
in  the  expression  for  "  volts  lost  "  and  we  have 

Volts  lost  =  (Nf=^)xCX2E  _  (N-m)X2E 

(N'  -f  N)  x  C  N2  +  N 

Now  substitute  this  value  for  "  volts  lost  "  in  equation  (5),  and 
for  "length  in  feet"  substitute  "d,"  and  for  current  (N—  m) 
x  C  ;  we  then  have 

c   m    =  d  X  (N  —  m)  XC  X   10.8  x  (N*  —  N) 

(N—  m)  x  2  E 
_  d  x  10.8  x  C  (N*  -f  N) 

~^E~  (9) 

The  supposition  of  uniform  size  of  conductor"  has  been  in- 
troduced above,  hence  this  equation,  true  for  any  section, 
gives  in  fact  the  cross-section  necessary  throughout  the  line. 


THE    LINE.  137 

Now  suppose  E  =  100,  N  =  10,  d  =  1,056,  we  then  have 

c.  m.  =  ii  X  264  X  3  X  10.8  =  94,087.6 
It  is  plain  that  formula  (9)  may  readily  be  converted  into 
one  having  more  direct  reference  to  the  whole  length  of  line. 

D 
Let  D  represent  that  length.     Then  d  =  ^;    substituting 

this  value  for  d  in  (9)  we  have 

D  X  (N  +  i)  C 
c.  m.  =  5.4-       -^^H-  (10) 

The  quantity  (N  -f-  i )  C  is  simply  the  total  current  required 
for  one  more  car  than  the  number  originally  in  view.  E,  it 
is  to  be  remembered,  represents  the  allowable  "  drop"  at  the 
end  of  the  line.  In  this  shape  the  formula  is  of  very  con- 
venient application. 

The  determination  of  the  area  of  the  conductor  made  above, 
as  applicable  to  case  I.,  is  evidently  applicable  also  to  cases 
II.  and  III.  The  differences  in  actual  construction  would 
be  as  follows:  In  case  I.,  the  whole  of  the  area,  94~,oS7.6  c. 
m.,  would  be  found  in  a  single  bare  trolley  wire.  In  case 
II.  this  area  would  be  found  partly  in  the  bare  trolley  wire 
and  partly  in  a  parallel  feeder.  Thus  suppose  a  No.  6  trolley 
wire  to  be  used,  of  about  40,000  c.  m.,  then  the  feeder  would 
have  to  be  about  55,000  c.  m.  in  area.  To  insulate  a  pound 
of  copper  with  the  material  used  ordinarily  in  weather-proof 
wires  costs  about  7  cents.  The  total  additional  cost  of  the 
feeder,  over  the  bare  wire,  is  found  by  taking  this  cost  per 
pound  and  adding  it  to  the  cost  of  placing  the  feeder  in 
position  and  connecting  it  to  the  trolley  wire.  These  two 
items  may  be  roughly  taken  at  $100  per  mile. 

In  case  III.  we  must  have  a  feeder  of  about  94,000  c.  m., 
since  the  continuity  of  the  trolley  wire  is  broken.  The  in- 
creased cost  over  either  of  the  other  two  methods  is  evident. 

It  has  been  assumed  above,  for  convenience,  that  the  re- 
sistance of  the  rail  and  earth  circuit  is  zero. 

Because  the  resistance,  under  favorable  conditions,  is  ex- 
tremely low  it  has  been  the  habit  of  some  engineers  thus 
to  rate  it  as  zero,  placing  all  the  allowable  resistance  in  the 
overhead  wires  and  reducing  them  to  one-half  the  cross- 
section  that  would  be  required,  if  the  outgoing  and  the  return 


j^g  THE    ELECTRIC    RAILWAY. 

branches  of  the  circuit  were  supposed  to  be  of  equal  resist- 
ance, as  in  the  case  of  the  double  trolley  system.  The  total 
weight  of  copper  overhead  would  thus  be  made  only  one- 
fourth  of  that  needed  for  the  double  trolley  system,  where 
the  length  and  cross-section  are  both  doubled,  as  compared 
with  the  single  trolley  or  ground-return  system.  The  facts 
do  not  seem  to  justify  entire  neglect  of  the  resistance  of  the 
ground  return.  Especially  does  this  seem  true  when  we 
consider  the  changes  of  moisture  in  the  earth,  the  rusting  of 
the  track,  the  gathering  of  dust  and  dirt  upon  it  (causing  an 
appreciable  resistance  between  the  wheels  and  the  rails)  and 
the  resistance  of  joints  from  rail  to  rail. 

The  specific  resistance  of  iron  is  well  known,  being  about 
six  times  as  great  as  that  of  copper.  The  cross-section  and 
the  length  of  the  rails  may  also  be  readily  determined,  hence 
the  actual  resistance  of  the  rail  return  (neglecting  joints) 
may  be  accurately  calculated.  It  may  be  taken  fully  into 
account^upposing  only  that  the  joints  be  so  bonded  together 
that  the  rails  may  be  considered  as  practically  continuous. 

It  is  in  assigning  a  value  to  the  earth  as  a  conductor  that 
the  greatest  uncertainty  exists.  Since  the  earth  becomes  a 
conductor  through  contact  with  the  rail,  it  is  evident  that  the 
manner  of  laying  the  track  and  the  nature  of  the  paving  laid 
along  the  track  must  materially  affect  the  quantity  of  current 
which  actually  leaves  the  rails.  Further,  the  nature  of  the 
soil  itself,  both  in  the  surface  stratum  and  in  the  lower  strata ; 
the  number  of  iron  pipes  (as  for  gas,  etc.)  placed  in  the 
ground;  the  proximity  of  large  bodies  of  water — all  these 
variables  will  affect  this  quantity.  Realizing  that  the  soil  is 
usually  to  be  found  permanently  moist  at  a  distance  of  sev- 
eral feet  below  the  surface,  electrical  engineers  very  early 
adopted  the  practice  of  connecting  the  rails  with  plates  or 
rods,  which  were  sunk  to  a  convenient  depth.  There  was 
some  gain  in  conductivity,  but  later  it  was  thought  best  by 
some,  on  account  of  telephone  disturbances,  to  aim  rather  at 
the  restriction  of  the  current  to  the  rail  than  at  its  dispersion 
through  the  earth.  To  utilize  perfectly  all  the  metal  in  the 
rails,  specifications  were  accordingly  drawn  up  looking  to 
their  thorough  bonding  both  longitudinally  and  laterally. 


THE    LINE.  139 

To  this  bonding  it  has  by  some  been  thought  wise  to  add  a 
continuous  copper  conductor,  supplementary  to  the  rails  and 
the  earth.  The  effect  of  this,  however,  is  generally  small, 
except  in  so  far  as  it  performs  the  function  of  a  bond-wire, 
rendering  more  certain  the  otherwise  difficult  maintenance 
of  a  good  circuit  around  the  joints ;  and  further,  in  that  it 
will  cause  the  potential  of  the  rails  and  the  earth  to  be  so 
nearly  identical  as  to  prevent  the  occurrence  of  the  slight 
shocks  sometimes  given  to  horses  while  resting  some  of  their 
iron-shod  feet  on  the  ground,  others  being  on  the  rail. 

In  view  of  all  the  uncertainty  as  to  the  quantities  involved 
and  all  the  variety  of  practice  in  treating  them,  it  need 
scarcely  be  added  that  there  has  been  considerable  variety 
in  the  results.  Fortunately,  any  error  of  under-calculation 
is  readily  corrected.  The  first  service  of  the  cars  over  the 
line  may  be  purposely  brought  to  the  conditions  of  maximum 
load.  The  speed  then,  or,  more  accurately,  the  readings  of 
a  voltmeter  on  a  car,  will  furnish  immediate  data  as  to  the 
sufficiency  of  the  copper,  or  will  detect  local  trouble  in  the 
rail  connections.  The  erection  of  an  additional  feeder,  or 
some  intelligent  work  on  the  bonds,  will  soon  set  matters 
right.  If,  on  the  other  hand,  the  pressure  on  the  line  shows 
somewhat  higher  than  was  calculated,  no  harm  is  done  and 
the  coal  consumption  has  been  permanently  reduced. 

While  the  assumption  of  any  definite  value  for  the  rail  and 
earth  resistance  (called  for  convenience  the  return  circuit), 
or  of  any  fixed  jatio  between  this  value  and  that  of  the 
resistance  overhead,  must  generally  be  in  error,  it  will  not 
be  unwise  to  present  a  rule  which  has  given  fairly  uniform 
results. 

Subject  to  modification,  whenever  it  is  possible  by  actual 
measurement  to  determine  the  rail-earth  resistance,  we  may 
use  without  large  error  the  following  modification  of  formula 
(10): 

,     D  X  (N  +  i)  C 
c.  m.  =6.5-       ±g±-  (n) 

This  calls  for  about  20  per  cent,  more  copper  than  is  required 
by  the  assumption  of  zero  resistance  in  the  return  circuit. 
Should  there  be  considerable  differences  in  the  quantities  of 


I40  THE    ELECTRIC    RAILWAY. 

current  required  by  uniformly  distributed  cars,  sufficiently 
accurate  results  will  yet  be  obtained  by  the  same  formula 
(n),  if  the  average  current  C  be  properly  determined. 
Should  there  be  considerable  "bunching"  of  cars,  the  re- 
quired copper  may  be  calculated  separately  by  the  general 
formula  (5)  (increasing  it  by  20  per  cent.,  as  above  in  (i  i)  ), 
the  "length  in  feet"  being  taken  from  the  station  to  the 
middle  point  of  the  section  (supposed  of  moderate  length)  on 
which  "bunching"  is  found;  and  the  required  areas  may 
then  be  summed.  If  it  be  desired  to  change  the  size  of  the 
feeder,  after  placing  any  length  S  A  from  the  station  to  A, 
the  area  up  to  A  may  be  determined  as  above,  a  fixed  "  drop  " 
being  then  allowed  (less  than  the  total  allowable)  and  the 
point  A  may  then  be  taken  as  a  new  datum  point  of  initial 
pressure.  By  diminishing  the  size  of  the  feeder  over  the 
part  nearer  the  station,  we  may  maintain  the  total  "drop"  at 
100  volts,  while  increasing  the  average  "drop"  beyond  the 
value  it  would  have  if  a  wire  of  uniform  diameter  were  placed 
along  the  whole  line  or  section. 

Failure  to  understand  this  relation  has  not  infrequently 
caused  copper  to  be  placed  where  it  could  not  do  the  greatest 
good.  Thus,  suppose  a  uniform  wire  gives  a  line  pressure  of 
450  volts  at  A  and  400  volts  at  B.  It  is  found  that,  there 
being  heavy  grades  at  B,  the  motors  become  unduly  heated. 
It  is  desired  to  increase  the  pressure,  thus  decreasing  the 
current  required  for  a  given  amount  of  work.  A  length  of 
wire,  S  A  =  A  B,  is  bought  and  (i)  is  placed  between  the 
station  and  A,  and  connected  at  intervals  to  the  trolley  wire; 
or  (2)  it  is  connected  only  at  S  and  at  A ;  or  (3)  it  is  con- 
nected at  A,  thence  at  intervals  along  A  B  to  B;  or  (4)  it  is 
connected  simply  at  A  and  B.  For  raising  the  pressure  at  B, 
the  fourth  is  the  most  efficacious  method ;  and  if  increase  of 
pressure  is  needed  at  B,  and  is  not  important  elsewhere,  the 
fourth  method  should  be  followed.  The  formulae  already 
given  will  show  the  distribution  of  pressures. 

In  treating  cases  IV.,  V.,  and  VI.,  there  are  required  two 
determinations  of  different  characters.  First,  to  determine 
the  diameter  of  the  feeders,  the  function  of  which  is  to  carry 
a  certain  current  over  a  certain  distance  at  a  certain  percent- 


THE    LINE.  141 

age  of  loss,  the  whole  current  to  pass  out  of  the  feeder  at 
one  point,  the  end.  Such  a  calculation,  made  by  formula 
(5),  is  very  simple.  It  should  be  borne  in  mind,  however, 
as  explained  above,  that  some  assumed  value  for  the  earth 
circuit  must  be  used.  The  general  formula  (5)  is 

length  in  feet  X  10.8  X  C 
c.  m.  —  — 

volts  lost 

If  we  were  to  use  a  double  metallic  circuit,  this  distance  in 
feet  would  be  the  distance  out  plus  the  distance  in  (return) . 
For  the  single  trolley  system,  however,  we  have  in  mind  the 
distance  measured  only  in  one  direction.  We  increase  the 
value  of  the  constant  10.8  by  20  per  cent.,  as  above,  and 
then  have 

length  in  feet  X  1 3  X  C 

c.  m.  =  —  (12) 

volts  lost 

The  value  of  C  in  this  formula  depends  upon  the  number 
and  service  of  the  cars  which  it  is  proposed  to  supply  by  the 
feeder  in  question.  The  volts  lost  must,  of  course,  be  less 
than  the  total  "drop,"  since  a  part  of  this  total  must  take 
place  on  the  trolley  wire,  or  on  trolley  wire  and  main,  as  in 
case  VI.  The  terminals  (feeding-in  points)  of  the  feeders 
become,  with  respect  to  the  trolley  wire,  points  of  initial 
pressure ;  and  the  second  calculation  to  be  made  consists  in 
the  determination  of  the  length  of  the  trolley  section  between 
feeding  points,  if  the  trolley  wire  (of  fixed  diameter)  be  used 
alone/  or  the  determination  of  the  diameter  of  the  mains  for 
a  fixed  distance  between  feeding  points.  This  latter  deter- 
mination would  be  entirely  analogous  to  that  made  above  for 
cases  I.,  II.,  and  III.  The  formula  to  be  used  is  that  for 
earth-return  (u).  The  same  formula,  slightly  transposing 
its  terms,  becomes 

volts  lost  (=  E) 
D  =  C-m-6.5X(N+,)C 
in  which  C  is  the  current  per  car,  or  per  short  section  into 
which  the  line  may  be  supposed  to  be  divided,  the  volts  lost 
being  the  difference  between  the  maximum  allowable  and 
the  "  drop "  on  the  feeder  alone,  from  station  to  feeding 
points.  If  the  pressures  at  these  points  be  maintained  prac- 
tically equal,  and  if  the  work  between  them  be  distributed 


I42  THE    ELECTRIC    RAILWAY. 

uniformly,  the  point  of  lowest  pressure  (maximum  "  drop  ") 
will  be  found  on  the  trolley  line  midway  between  feeder  ends. 

By  the  system  of  independent  feeders  the  pressure  may 
readily  be  made  higher  at  some  point  distant  from,  the  station 
than  at  some  point  near  it.  And  if  the  work  at  any  distant 
point  be  very  trying,  the  establishment  of  such  differences 
may  be  wise. 

Since  No.  o  has  been  largely  used  for  the  trolley  wire,  it 
may  be  well  to  deduce  from  formula  (13)  the  distance  over 
which  it  alone  may  supply  current  to  a  given  number  of  cars. 
Let  us  assume,  as  heretofore,  that  400  volts  is  the  minimum 
allowable  line  pressure;  assume,  further,  that  we  maintain 
450  volts  at  the  feeder  ends.  Then  the  total  "  drop  "  over 
the  trolley  must  not  exceed  50  volts.  A  mean  between  the 
Birmingham  and  Brown  &  Sharpe  gauges  gives  110,000 
for  No.  o.  Suppose,  further,  that  we  have  about  10  cars  to 
the  mile,  or  150  amperes  total  current.  Then 

D  =  1 10,000 g-^^  -  5,641  feet. 

For  any  other  car  service  the  distance  is  readily  found. 

In  large  systems,  having  lines  crossing  and  recrossing  each 
other,  there  will  arise  some  rather  perplexing  questions  as  to 
potential  distribution.  The  simple  formulas  (11),  (12),  and 
(13)  will  serve  all  practical  purposes;  since,  after  all,  the 
whole  matter  consists  in  a  sometimes  complicated  application 
of  Ohm's  law. 

Except  in  the  matter  of  the  rail-and-earth  circuit,  all  that 
has  thus  far  been  said  applies  equally  well  to  the  single  and 
double  trolley  systems.  The  latter  has  now  been  almost 
wholly  superseded  by  the  former.  There  are  three  reasons 
for  the  survival  of  the  single  trolley  method  as  the  fittest : 
first,  greater  simplicity  of  overhead  turn-outs  and  frogs,  in 
so  far  as  the  mechanical  operation  of  the  trolley  is  concerned, 
and  this  is  the  controlling  reason;  second,  greater  facility  in 
insulating  the  out-going  from  the  in-going  side  of  the  circuit, 
for  when  the  rail  return  is  used  these  sides  are  about  1 8  feet 
apart,  while  with  the  double  trolley  wire  they  are  from  8  to 
18  inches  apart;  third,  greater  economy  of  copper  in  large 
systems.  This  advantage  is  not  as  great  as  has  appeared 


THE    LINE.  143 

from  the  comparisons  already  given  in  discussing  the  copper 
calculations.  An  offset  must  be  made  by  considering  the 
cost  of  bonding  the  rails  thoroughly,  as  compared  with  the 
cost  of  supplying  and  erecting  the  copper  return,  which  would 
serve  instead  of  the  rails  and  earth.  In  case  of  very  light 
service,  the  first  cost  may  be  less  for  the  double  than  for  the 
single  trolley  system.  A  fourth  advantage  is  usually  claimed, 
in  that  fewer  wires  are  actually  required  to  be  erected,  thus 
diminishing  the  objections  made  to  the  whole  trolley  system 
merely  on  the  score  of  "looks."  To  this,  the  advocates  of 
the  double  trolley  (for  there  are  a  few)  answer  that  in  either 
system  all  feeder  wires  may  be  buried ;  that  the  comparison 
would  then  rest  as  between  bare  wires  alone ;  that  the  single 
trolley  wire  requires  one  or  two  guard  wires,  stretched  par- 
allel to  each  "live  "  wire,  and  these  guard  wires  require  span- 
wires  for  their  support — this  being  done  to  prevent  foreign 
wires  from  falling  across  the  "  live  "  wire  and  to  the  ground, 
where  they  rriay  or  may  not  make  such  contact  as  will  cause 
them  to  be  entirely  burned  out ;  that  the  double  trolley  sys- 
tem does  not  require  guard  wires,  since  in  case  of  any  foreign 
wire  crossing  the  two  live  wires  it  would  at  once  be  destroyed 
and  the  trouble  at  the  railway  station  would  end. 

There  has  been  so  little  extension  of  this  double  trolley 
system  that  it  cannot  now  be  stated  whether  or  not  the  pub- 
lic authorities  would  generally  allow  this  difference  of  con- 
struction as  between  the  two  systems.  It  does  not  seem 
probable.  In  Cincinnati,  Ohio,  where  the  Cincinnati  Street 
Railway  Company  has  produced  the  most  notable  example 
of  double  trolley  service,  guard  wires  were,  however,  not 
erected. 

The  advantages  of  the  double  trolley  system  are  two :  First, 
it  causes  little  interference  with  the  telephone  circuits  that  use 
ground  return  in  the  neighborhood  of  the  railway  lines. 
This  has  been  the  cause  of  much  litigation,  urged  by  the 
telephone  interests,  endeavoring  to  force  the  use  of  that  sys- 
tem of  electric  railways  which  would  least  interfere  with  the 
established  telephone  service.  Thus  far  the  courts  have 
ruled,  for  the  most  part,  against  such  requirements. 

The  case  of  the  telephone  labors  under  this  disadvantage: 


I44  THE    ELECTRIC    RAILWAY. 

that  it  strives  to  destroy  the  most  practical  system  of  railway 
circuits  in  order  to  continue  a  relatively  poor  system  of  tele- 
phone circuits.  The  remedy  for  the  evils  brought  upon  the 
telephone  service  by  the  disturbing  earth  currents  of  the 
railway  service  is  to  be  found  in  the  use  of  complete  metallic 
circuits  for  the  one  or  the  other  or  both.  To  apply  the  rem- 
edy to  the  telephone  circuits  is  to  produce  the  only  installa- 
tion which  may  be  called  first-class,  with  or  without  consid- 
eration of  railways.  The  currents  required  for  telephones 
are  exceedingly  small;  the  forces  by  which  they  may  be 
disturbed  are  correspondingly  small.  To  insist  that  when 
passing  through  the  earth  these  currents  shall  not  be  percep- 
tibly disturbed  by  other  currents,  is  to  insist  upon  a  practical 
monopoly  of  the  earth  as  part  of  an  electric  circuit.  The 
best  English  and  European  telephone  practice,  uninfluenced 
by  any  trouble  from  railway  currents,  tends  decidedly  toward 
complete  metallic  circuits.  To  apply,  on  the  other  hand,  the 
same  remedy  to  the  railways,  is  to  impose  seri'ous  difficulties 
in  the  way  of  the  practical  success  of  the  operation  of  cars 
over  the  complexities  of  switches,  turn-outs,  cross-overs,  and 
the  like.  It  will  afford  a  pleasing  exercise  of  ingenuity  to 
plan  overhead  apparatus  suitable  for  the  following  conditions  : 
The  double-tracked  road  of  one  company  has  single-tracked 
branches,  one  to  the  right,  one  to  the  left,  at  a  given  street 
crossing,  while  continuing  its  double-tracked  course  beyond  the 
point  of  junction.  The  double-tracked  road  of  another  com- 
pany crosses  that  of  the  first  at  this  point  of  junction,  running 
parallel  to  the  branches.  The  twTo  companies  refuse  inter- 
change of  current  and  want  to  use  the  double  trolley  system. 

We  cannot  do  better,  in  setting  forth  more  fully  the  merits 
of  this  controversy,  than  to  give  the  opinions  of  the  Superior 
Court  of  Cincinnati,  and  the  Supreme  Court  in  the  State  of 
Ohio.  These  are  found  in  Appendix  A. 

The  second  advantage  to  be  noted  is  this:  that  effective 
insulation  of  the  motor  windings  may  be  more  readily  secured 
than  in  the  case  of  the  rail-return  circuit.  In  the  earlier 
stages  of  the  art,  this  was  indeed  an  important  advantage ; 
for  on  the  single  trolley  roads  no  accident  was  more  common 
than  the  "  grounding  "  of  armature  or  field  coils.  Previous 


THE    LINE.  145 

practice  in  winding  for  comparatively  high  potentials  had 
rarely  to  deal  with  the  case  in  which  the  metal  of  the  machine 
was  in  fact  part  of  the  circuit.  To  produce  a  short  circuit 
through  the  body  of  the  dynamo,  it  was  generally  necessary 
that  the  insulation  of  the  wires  should  break  in  at  least  two 
points  of  different  potential.  When,  however,  one  brush  of 
the  motor  was  connected,  as  was  often  the  case,  directly  to  the 
motor  frame  (this  latter  being  hung  on  the  axle,  whence 
the  current  passed  to  the  wheels) ,  it  needed  a  break  at  but  a 
single  point  to  cause  trouble.  In  the  violent  fluctuations  of 
current  strength  and  magnetic  density  incident  to  car  service, 
there  were  often  produced  very  high  electromotive  forces  of 
induction,  and  these,  if  not  the  normal  pressure  of  500  volts, 
often  destroyed  the  insulation  of  armature  or  field.  In  some 
designs  this  trouble  has  been  practically  met  by  attempting 
to  insulate  the  frame  of  the  motor  from  the  car  truck.  This 
will  be  seen  to  impose  considerable  mechanical  difficulty. 
Generally,  so  much  improvement  has  been  made  in  the  details 
of  armature  and  field  winding,  that  the  matter  has  ceased  to 
be  big  with  misfortune,  as  was  once  the  case. 

There  are  now  in  the  United  States  not  more  than  ten 
double  trolley  lines,  only  one  of  which,  that  at  Cincinnati,  is 
of  what  may  be  called  a  modern  construction — that  is,  built 
within  the  last  two  years.  Of  single  trolley  lines  there  are 
several  hundreds. 

The  third  method  of  power  supply,  involving  an  extensive 
conducting  system,  is  that  through  underground  conduits. 
Thus  far,  all  efforts,  and  they  have  been  many  and  ingenious, 
successfully  to  insulate  the  conductors  in  a  conduit,  have 
failed,  save  when  topographical  conditions  were  very  favor- 
able. Some  of  these  efforts  will  be  described  elsewhere. 
The  principles  governing  the  calculation  of  copper,  as  already 
set  forth,  will  of  course  apply  to  conductors  underground  as 
well  as  overhead. 

It  should  be  stated  that  in  using  the  rail-and-earth  return 
it  is  desirable  to  avoid  setting  up  a  high  current  density  in 
the  earth  at  points  along  the  line  or  at  the  station.  When  the 
line  current  is  very  great  there  may  occur  localized  earth 
currents  of  such  magnitude  as  to  seriously  interfere  with  un- 


I4<5  THE    ELECTRIC    RAILWAY. 

dergrotmd  circuits  or  even  to  produce  considerable  electric 
effects  on  metallic  pipes  or  cables.  As  this  condition  is  un- 
likely to  exist  except  in  roads  with  very  heavy  traffic,  where 
railroads  are  necessarily  inadequate,  it  wTould  seem  best  to 
use  in  such  cases  numerous  ground  plates  along  the  line  and 
especially  at  the  station,  placing  them  below  the  level  of  water 
and  gas  pipes  and  in  moist  earth.  This  will  both  raise  the 
general  conductivity  and  avoid  high  local  current  densities  in 
the  earth. 

We  have  now  treated  the  subject-matter  of  this  chapter  in. 
its  more  general  aspects,  and  in  Appendix  B  will  be  found  a 
set  of  instructions  for  the  erection  of  an  overhead  line. 

There  are  now  on  the  market  many  varieties  of  insulators, 
frogs,  pole  clamps,  etc.  Simply  for  the  sake  of  consistency, 
throughout  the  instructions,  some  special  types  are  referred 
to.  Modifications  may  readily  be  made  in  such  of  the  lan- 
guage as  applies  only  to  particular  forms  or  dimensions.  It 
is  intended  simply  to  illustrate  the  general  mechanical  rules 
which  should  be  observed. 

We  go  into  considerable  detail  in  these  specifications  be- 
cause many  railway  companies  now  prefer  to  do  this  work 
directly  rather  than  through  contractors. 

For  much  of  what  is  valuable  in  them  we  are  indebted  to 
Mr.  W.  E.  Baker,  of  Boston,  who  prepared  similar  instruc- 
tions, which  we  have  slightly  modified  for  this  publication. 


CHAPTER   V. 

TRACK — CAR    HOUSES — SNOW    MACHINES. 
TRACK. 

FOR  half  a  century  steam-railway  engineers  have  studied 
track  construction.  Great  advances  have  been  made  in  the 
last  ten  years,  and  change  is  still  considerable;  this  means 
that  the  present  railroads  are  not  perfect,  are  not  final ;  yet, 
withal,  the  steam-railway  practice  is  the  best  guide  in  a  gen- 
eral way  for  street-railway  men  using  electric  cars  to  follow. 
True,  the  conditions  as  to  pavement  and  wagon  traffic  are 
widely  different  in  the  two  cases,  and  render  the  street- 
railway  problem  for  a  given  weight  of  car  or  locomotive 
much  the  more  difficult  of  the  two.  But  it  remains  that  the 
best  track,  considered  simply  as  to  the  company's  own  traffic, 
is  in  both  cases  the  approved  "T"  rail  construction  found 
generally,  with  varying  detail,  on  our  steam  railways. 

To-day  the  problem  of  track-construction — especially  that 
of  joint  construction — is  perhaps  the  most  important  one 
pressing  upon  street-railway  men  for  their  attention. 

It  is  beyond  the  scope  of  this  work  to  give  a  treatise  on 
track  construction;  we  desire,  however,  to  present  a  few 
•examples  of  good  practice — at  least,  of  that  which  is  good 
now.  Much  must  yet  be  learned  in  this  matter. 

Broadly  speaking,  light  track  construction  must  give  way 
to  heavier  construction.  Meanwhile  we  show  in  Fig.  75  the 
construction  at  present  largely  used  by  the  West  End  Rail- 
way Company  of  Boston;  in  Fig.  76  the  track  used  by  the 
Pittsburg,  Allegheny  and  Manchester  Traction  Company, 
and  in  Fig.  77,  that  toward  which  the  West  End  Compan)T 
of  Boston  now  leans.  This  last  is  noteworthy,  in  that  the 
chairs  are  electrically  welded  to  the  rail,  the  only  bolts  used 
being  those  at  the  fish  plates.  To  reach  these  from  time 
to  time  a  joint  box  has  been  advised,  which  is  shown  in 
Fig.  78.  This  permits  ready  access  to  the  nuts  on  the  out- 


148 


THE   ELECTRIC    RAILWAY. 


side  of-  the  rails,  so  that  they  may  be  inspected  and  set  up 
frequently  and  with  little  trouble.  One  side  of  the  box 
serves  as  a  fish  plate,  the  bottom  as  a  chair. 

Through  the  kindness  of  Mr.  F.  H.  Monks,  General  Man- 


FIG.  75.— TRACK  CONSTRUCTION  OK  WEST  END  STREET  RAILWAY  COMPANY. 

ager  of  the  West  End  Street  Railway  Company,  we  also  show, 
in  Figs.  79  and  80,  a  large  number  of  rail  sections  used  in 
various  parts  of  the  country.  The  lighter,  especially  the  flat 
sections,  have  seldom  been  laid  originally  for  electric-car 
service.  There  is,  however,  almost  no  type  of  track  so 


CONCRETE 


FIG.  76.— TRACK  CONSTRUCTION  OF  P..  A.  &  M.  TRACTION  COMPANY. 

poor  but  that  some  bold  operator  has  been  willing  to  use  it 
as  a  destroyer  of  electric  apparatus  and  of  dividends. 

We  will  close  this  very  short  treatment  of  this  subject  by 
the  following  quotation  from  a  very  excellent  and  succinct 
letter  recently  addressed  by  Mr.  F.  H.  Monks,  General  Man- 


TRACK — CAR    HOUSES — SNOW    MACHINES 


149 


ager  of  the  West  End  Street  Railway  Company  of  Boston, 
Mass.,  to  the  Street  Railway  Journal : 

"  The  coming  construction  for  electric  roads  will  contain 
but  few  jimcracks  to  break,  wear  out,  and  rust  away.  Strength 
and  durability  are  surely  the  qualities  which  should  be  sought. 
Since  the  problem  is  so  nearly  akin  to  that  which  steam  roads 
have  solved,  why  not  follow  closely  on  their  lines,  so  far  as 
is  possible,  adding  only  such  parts,  forms,  and  appliances  as 
may  be  necessary  to  conform  to  the  difference  in  the  condi- 
tions under  which  the  two  are  laid  and  operated  ?  The  writer 
suggests  the  following: 

"  Ties.  Sound  oak  or  chestnut,  six  and  one-half  feet  long, 
six  inches  face,  five  inches  thick,  placed  three  feet  on  cen- 


FIG.  77.— PROPOSED  RAIL  FOR  WEST  END 
COMPANY. 


FIG.  78.- JOINT  Box  OF  WEST  END 
COMPANY 


ters,  and  two  ties  set  eight  inches  apart  under  each  rail 
joint. 

"  Gravel.  Sharp,  clean,  free  from  loam  and  clay.  Tamp 
thoroughly  under  and  between  ties,  particularly  in  case  of 
those  carrying  rail  joints. 

"  Rail.  A  girder  of  sufficient  total  height  to  allow  two  inches 
of  gravel  between  top  of  tie  and  bottom  of  paving  stone; 
head  of  rail  two  and  one-eighth  inches,  flat  flange  two  and 
three-quarter  inches,  web  one-half  inch  to  nine-sixteenths  of 
an  inch,  lower  flange  five  and  one-half  inches  to  six  inches. 
Rail  to  be  laid  directly  on  ties  and  spiked  thereto  by  railroad 
hook  spikes  four  and  one-half  inches  long.  Rail  to  weigh 


1 5o 


THE    ELECTRIC    RAILWAY. 


about  one  hundred  pounds  per  yard,  and  to  be  drilled  for 
copper  connections,  tie  bars,  and  splice  bars. 


FIG.  79— TYPES  OF  AMERICAN  RAILS  FOR  ELECTRIC  TRAMWAYS 

"  Tie  bars.  Flat  iron  bars  six  feet  apart,  round  and  threaded 
ends,  to  pass  through  \veb  of  rails  and  set  tight  by  proper 
nuts. 


TRACK — CAR    HOUSES — SNOW    MACHINES. 


"  Splice  bars.     Thirty-inch  steel  channel  bars,  well  fitted  to 
rail,  and  so  drilled  for  six  bolts  as  to  allow  for  expansion  and 


FIG.  SO.-TYPES  OF  AMERICAN  RAILS  FOR  ELECTRIC  TRAMWAYS. 


contraction  of  rail.  Best  quality  bolts  and  nuts  to  be  used. 
Head  of  bolt  to  be  continually  struck  with  twelve-pound 
hammer  when  nut  is  being  set  up. 


I52  THE   ELECTRIC    RAILWAY. 

"  Joint  boxes.  Heavy  cast-iron  boxes  with  removable  covers, 
corrugated  tops,  to  be  placed  on  and  spiked  to  ties,  and  set 
outside  track  at  each  rail  joint,  thus  permitting  of  frequent 
and  inexpensive  joint  inspection  and  repair. 

"  As  it  is  intended  in  this  paper  to  consider  the  question  of 
track  construction  alone,  no  mention  need  be  made  of  elec- 
trical connection  of  rails.  Pave  with  block  stone  in  the  usual 
manner,  using  only  clean,  dry,  sharp  gravel.  As  authorities 
differ  regarding  the  question  of  placing  rails  so  that  joints 
will  be  opposite  or  otherwise,  each  company  must  decide  for 
itself.  It  will  be  noted  by  this  mode  of  construction  that 
steam-railroad  practice  is  closely  followed.  Here  are  no 
chairs,  stringers,  or  other  supports.  There  are  but  seven 
parts  in  construction,  namely,  ties,  rails,  tie  bars,  spikes, 
splice  bars,  bolts  and  nuts,  and  boxes.  Aside  from  excava- 
tion, gravel,  and  paving,  this  track  should  be  built  for  about 
$10,500  per  mile  of  single  track.  Many  will  doubtless  say 
that  such  cost  of  construction  is  prohibitive,  but  a  fair  answer 
thereto  is,  that  it  will  solve  the  vexing  question  now  con- 
fronting electric  street-railway  men  in  all  large  cities,  of  how- 
to  build  a  track  which  will  stand  the  severe  strain  now  put 
upon  it,  which  can  be  maintained  and  kept  in  repair  at  min- 
imum cost.  The  first  cost  above  named  is  entirely  justifiable 
and  warranted." 

CAR    HOUSES. 

The  arrangement  of  car  houses  for  electric  railways  must 
differ  from  that  familiar  in  horse-railway  practice  in  that 
provision  must  be  made  for  readily  inspecting,  removing, 
replacing,  and  repairing  the  motors.  To  accomplish  this 
inspection,  removal,  and  replacement  it  has  been  customary 
to  excavate,  between  the  rails  of  car-house  tracks,  pits  of  four 
to  six  feet  in  depth.  When  an  easy  approach  from  the  street 
can  be  made  the  tracks  may  be  elevated,  leaving  proper 
working  space  between  the  level  of  the  track  and  that  of  the 
floor.  Some  question  arises  as  to  the  required  length  of  pit 
room  as  compared  with  the  total  length  of  car-house  track- 
age. This  ratio  must  depend  upon  the  number  of  injuries 
to  mechanism,  which  in  turn  depends  on  the  quality  of  the 
machinery  and  the  quality  of  the  service  maintenance. 


TRACK — CAR    HOUSES — SNOW    MACHINES.  153 

It  may  be  roughly  stated  that  pit  room  should  be  sup- 
plied for  at  least  one  car  out  of  ten  in  service.  If  the  excava- 
tion and  protection  of  the  pit  space  be  not  costly  it  will  be 
well  considerably  to  increase  this  proportion.  We  show  in 
Fig.  8 1  a  very  convenient  machine  used  by  the  East  Cleveland 
Street  Railway  Company,  Cleveland,  Ohio,  for  the  expeditious 
handling  of  motors  in  the  pits..  An  hydraulic  hoisting  appa- 
ratus having  a  vertical  range  of  a  foot  or  more  is  mounted 
in  a  low  truck  which  runs  on  light  rails  laid  in  the  pit.  The 
cut  shows  a  motor  on  the  platform  of  the  hoist  ready  to  be 


FIG.  81.— HYDRAULIC  HOIST  FOR  HANDLING  MOTORS. 

lowered  or  raised.  It  is  clear  that  a  motor  or  any  of  its 
heavier  parts  may  thus  be  handled  with  much  less  time  and 
labor,  and  with  more  safety,  than  by  the  "  slings"  or  "  main 
strength  and  awkwardness  "  not  infrequently  employed.  It 
is  in  the  pit  that  the  closest  acquaintance  with  the  motor 
itself  can  be  formed.  We  know  of  one  large  company  which 
requires  division  superintendents,  inspectors,  and  motor-men 
to  serve  a  period  in  the  pit,  until  the  electrical  department  of 
the  company  shall  certify  to  the  fitness  of  the  employee  for 
the  discharge  of  his  duty. 

In  order  to  store  cars  at  night  quickly,  and  to  get  particular 


154  THE    ELECTRIC    RAILWAY. 

cars  out  quickly  when  ready,  most  companies  of  considerable 
size  have  used  transfer  tables — usually  running  near  the  front 
of  the  car  house.  Those  that  have  been  employed  for  the 
ordinary  horse  cars  may,  of  course,  be  used  for  electric  cars. 
We  show  in  Fig.  82  a  transfer  table  used  by  the  West  End 
Company  of  Boston.  It  is  propelled  by  a  cable,  which,  in 
turn,  is  operated  by  a  stationary  motor,  the  controlling  appa- 
ratus for  which  is  placed  at  one  end  of  the  transfer  table. 
Another  feature  of  this  installation  consists  in  the  fact  that  a 
car  may  cross  the  pit  to  the  leading-out  track  just  opposite 
that  on  which  the  car  may  be  standing.  The  tracks  are 
made  continuous  across  the  transfer  pit  by  short  inclined 
rails  covering  the  difference  of  level  between  the  floor  proper 
and  the  bottom  of  the  pit,  whereon  are  laid  also  the  rails  on 
which  the  car  crosses  the  pit.  The  crossings  of  these  rails 


FIG.  82.-SECTION  OF  TRANSFER  TABLE. 

with  the  rails  on  which  the  table  runs  are  of  course  quite 
numerous,  but  the  great  facility  of  car  movement  thus  gained 
is  worth  much  to  a  road  working  its  cars  on  a  close  schedule. 

In  order  to  avoid  the  frequent  climbing  upon  the  car  top 
to  inspect  the  trolley,  the  East  Cleveland  Street  Railway 
Company  has  arranged  a  raised  platform  by  the  side  of  an 
entering  track  to  the  car  house  in  such  a  manner  that  the 
inspector  is,  when  on  the  platform,  at  the  proper  level  to 
inspect  the  trolley. 

Such  a  construction  costs  but  little  money,  and  it  has  been 
already  a  source  of  much  satisfaction  to  the  management. 
Fig.  83  *  has  been  drawn  from  a  photograph  of  this  arrange- 
ment. 

Near  the  car  house — preferably   under  the    same    roof 

should  be  placed  the  repair  shop.  If,  as  in  a  larger  system, 
there  be  several  car  houses,  the  principal  repair  shop  should 

"011^  "^  kmdness  °f  Mr'  C'  W'  Wason'  General  Manager  East 


TRACK — CAR    HOUSES — SNOW    MACHINES. 


155 


be  near  one  of  the  largest  car  houses,  or,  if  that  is  not  con- 
venient, near  the  station.  The  machinery  of  such  a  shop 
may  be  run  conveniently  by  a  stationary  electric  motor.  A 
company  operating  cars  even  as  few  in  number  as  ten  will 
find  it  not  unprofitable  to  become  the  owners  of  a  few  good 


FIG.  83.— PLATFORM  FOR  READY  ACCESS  TO  TOP  OF  CARS. 

machine  tools.  A  lathe  and  a  drill  press  are,  of  course,  the 
most  generally  useful.  We  cannot  pretend  to  give  here  any 
valuable  advice  as  to  just  how  far  a  railway  company  should 
go  in  the  manufacture  of  repair  parts.  Local  facilities  and 


156 


THE    ELECTRIC    RAILWAY. 


the  personal  qualities  of  the  management  must  determine 
that  question.  We  can  only  suggest  that  when  either  tools 
or  men  in  the  repair  shop  are  found  to  be  idle  half  their 
time,  question  should  be  raised  as  to  the  wisdom  of  keeping 
them  in  service.  It  may  well  be  cheaper  to  carry  a  liberal 
stock  of  spare  parts.  In  the  repair  shop,  perhaps  even  more 
than  in  other  parts  of  the  plant,  is  the  value  of  order  and 
neatness  displayed.  Have  a  separate  bin  for  each  kind  of 
supplies ;  keep  the  floor  well  swept ;  especially  have  an  eye 
to  metal  filings;  keep  the  winders  and  their  supply  of 
wire  well  away  from  litter  of  any  kind;  keep  armatures  in 
racks,  not  on  the  floor,  where  they  may  easily  be  bruised ; 
have  plenty  of  light,  either  natural  or  artificial ;  keep  a  record 
of  every  armature  and  field  repair,  giving  to  each  its  number, 
date,  and  character  of  injury;  if  you  manufacture  supply 
parts  look  well  to  their  cost,  that  you  may  be  sure  as  to  the 


FIG.  84. -HYDRAULIC  JACK  FOR  REPAIR-SHOP  USE 

wisdom  of  making  them  at  home  or  purchasing  from  dealers; 
if  you  rewind  armatures  or  fields  manage  to  have  at  least  a 
5OO-volt  current — if  not  something  higher  from  an  adjacent 
lighting  circuit — with  which  to  test  the  parts  in  the  shop 
before  replacing  in  the  motor,  remember  that  your  winders 
should  have  good  will  as  well  as  skill — their  capacity  to  do  harm 
easily  is  great;  repair  injured  parts  as  soon  as  possible  after 
discovery  of  the  injury ;  have  a  care  to  get  good  mechanics — 
not  electricians — for  the  work  of  the  shop.  A  man  who  has 
been  "handy"  with  tools  all  his  life  will  devise  economical 
ways  of  doing  the  work.  If  the  repair  shop  is  of  considerable 
magnitude  he  will  design  a  few  special  tools  that  will  quickly 
pay  for  themselves.  This  should  not  be  construed  as  mean- 
ing that  the  number  of  special  devices  needed  is  considerable. 
As  a  suggestion  for  effort  in  the  right  direction  we  show 


TRACK — CAR    HOUSES — SNOW    MACHINES. 


157 


in  Fig.  84  an  hydraulic  press,  valuable  for  pulling  off  or 
pressing  on  commutators,  pinions,  or  gears,  or  almost  any 
other  use  involving  a  straight  pull  or  push. 

This  machine  was-  made  for  its  own  use  by  the  East  Cleve- 
land Street  Railway  Company. 

SNOW    MACHINES. 

To  remove  snow  wholly  from  city  streets  seems  beyond 
the  power  or  the  will  of  most  municipalities.  Certainly,  in 
many  cities  of  the  United  States  such  removal  would  be  a 
task  beyond  reason.  The  work  of  the  electric-railway  com- 


FIG.  85.— SNOW  PLOW  FOR  ELECTRIC  ROAD. 

pany  is,  then,  to  displace  the  snow  from  its  tracks;  for  this 
purpose  "  plows"  and  "  sweepers"  have  been  used.  Both  were 
already  familiar  in  the  service  of  horse  railways.  For  perfect 
cleaning  of  the  track  both  seem  necessary. 

It  has  been  thought  by  the  management  of  one  of  the 
largest  electric-railway  corporations  that  the  sweeper  does 
its  work  too  well — in  this,  that  other  vehicles,  traveling  on 
runners,  are  so  much  interfered  with  by  the  cleanly-swept 


158  THE    ELECTRIC    RAILWAY. 

rails,  and  in  turn  so  much  interfere  with  cars  that  it  is  best 
to  leave  an  inch  or  two  of  snow  on  the  track,  as  when  cleared 
by  plows.  Unless  the  snow  is  very  much  compacted,  or  has 
become  a  sort  of  frozen  slush,  it  is  then  possible  to  obtain 
fair  contact  between  wheel  and  rail,  thus  keeping  up  the  car 
service.  It  is  intended  to  prevent  packing  and  freezing  by 
prompt  and  constant  use  of  the  snow  plows.  Holding  these 
views,  the  corporation  in  question  has  supplied  itself  with 
plows  only,  and  these  of  simple  type,  such  as  are  used  in 
connection  with  horses.  The  plow  is  driven  by  two  15  or  20 
horse-power  motors,  one  for  each  axle,  the  motors  being  on 
a  platform  protected  by  a  cab,  and  driving  through  the  me- 
dium of  sprocket  chains.  It  is  shown  in  Fig.  85.  Such  a 


FIG.  86,-SNOw  SWEEPER  FOR  ELECTRIC  ROAD. 

machine  is  of  course  less  expensive  to  maintain  than  a 
sweeper.  Other  companies,  on  the  contrary,  use  sweepers 
only.  If  the  question  of  sleighs  be  of  small  importance,  and 
the  snows  rather  light,  it  would  seem  that,  as  between  the 
two  machines,  if  only  one  can  be  had,  the  sweeper  would  be 
We  show  in  Fig.  86  a  snow  sweeper  run  by  three  15 
horse-power  electric  motors,  two  for  the  axles  and  one  for 
the  brushes,  or  revolving  brooms. 

The  sweeper  brooms  are  both  driven  from  a  single  counter- 


TRACK — CAR    HOUSES — SNOW    MACHINES.  159 

shaft  placed  on  the  deck,  this  shaft  being  on  the  same  angle 
as  the  broom  shafts,  and  consequently  parallel  to  both  of 
them  The  sprocket  wheels  are  on  each  end  of  the  counter- 
shaft, one  for  the  front  broom  and  one  for  the  rear  broom. 
The  object  of  using  but  one  counter-shaft  on  the  deck  of  the 
sweeper  is  that  it  gives  more  room  to  the  motor-men.  The 
sprocket  chain  which  drives  the  brooms  raises  and  lowers  on 
a  radius,  so  that  the  chain  is  always  kept  tight  and  the  possi- 
bility of  its  ever  dropping  from  the  sprocket  wheels  is  pre- 
vented. 

A  powerful  machine  that  claims  to  combine  the  functions 


FIG.  87.— COMBINED  SNOW  PLOW  AND  SWEEPER. 

of  plow  and  sweeper  is  shown  in  Fig.  87.  The  flier,  or 
rotating  brush  and  plow,  has  a  number  of  steel  blades  disposed 
much  as  are  the  buckets  of  a  steamboat  paddle  wheel.  It 
also  carries  steel  brushes,  one  brush  parallel  to  and  touching 
each  steel  blade.  The  brushes  extend  beyond  the  blades 
about  two  inches,  thus  clearing  away  the  snow  or  ice  which 
has  not  been  cut  away  by  the  blades.  Each  flier  is  driven 
at  a  high  speed  by  a  motor  of  15  to  25  horse-power.  By 
vertical  adjustment,  this  machine  will  leave  either  a  perfectly 
clean  road-bed  or  a  light  covering  of  snow,  the  rails  being 
clean  in  both  cases. 

The  combination  is  expensive,  compared  to  the  simple 
plows  and  sweepers,  and  whether  its  value  is  in  proportion 
to  its  expense  remains  for  the  present  winter  to  determine. 


160  THE    ELECTRIC    RAILWAY. 

Salt  should  not  be  used  for  removal  of  snow  unless  nothing 
else  is  at  hand.  Its  use  is  likely  to  cause  rapid  corrosion  of 
the  rail  bonds.  The  lesson  most  distinctly  taught  during 
the  few  winters  whose  snows  have  fallen  on  electric  railways 
is  this:  "Do  not  let  the  snow  get  ahead  of  you."  A  watch- 
man should  inform  the  proper  authority  of  any  considerable 
fall  occurring  after  service  hours,  steam  in  at  least  one  en- 
gine should  be  kept  up  for  immediate  use,  and,  generally, 
everything  should  be  in  readiness  at  all  times  for  putting  the 
snow  gang  at  work  within  one  hour,  or  less,  from  the  start. 
Such  a  course  is  hard  to  follow,  perhaps,  but  it  pays. 


CHAPTER  VI. 

THE   STATION. 

ONE  of  the  first  questions  that  arises  in  the  construction  of 
an  electric  railway  is,  naturally,  the  position  and  character 
of  the  power  station.  It  is  not  at  all  a  simple  matter,  for 
there  enter  into  it  considerations  of  a  rather  complicated  nat- 
ure, all  having  a  direct  bearing  on  the  economy  of  the  future 
system.  It  is  needless  to  say  that  the  line  should  first 
be  roughly  located,  in  order  to  arrive  at  an  intelligent  un- 
derstanding of  the  conditions  that  must  be  fulfilled.  This 
done,  the  subject  of  the  proper  location  of  the  station  can  be 
taken  up. 

So  far  as  its'  position  with  reference  to  the  line  is  concerned, 
it  is  perhaps  sufficient  to  say  that,  other  things  being  equal, 
it  should  be  as  nearly  central  as  possible.  In  the  chapter  on 
line  construction  enough  is  said  to  impress  upon  the  mind  the 
conditions  imposed  by  the  distribution  of  the  copper,  but  it 
should  be  remembered  that  the  line  is,  comparatively  speak- 
ing, a  permanent  investment,  and  from  the  relatively  small 
interest  charges  and  repairs  it  does  not  involve  an  im- 
portant part  of  the  expenses. 

In  any  given  station,  whatever  its  position,  a  considerable 
item  of  the  running  expenses  will  be  labor,  and  this  is  virtu- 
ally independent  of  position.  The  factor  that  should  go 
farthest  in  determining  the  proper  location  is  the  availability 
of  fuel.  If  it  is  possible,  the  power  station  should  be  so 
placed  that  coal  cars  can  be  run  up  to  its  very  door  and  the 
fuel  shoveled  directly  into  the  coal  bins.  In  some  few  favored 
t>laces  an  arrangement  even  nearer  the  ideal  has  been  found 
possible,  as,  for  example,  in  Scranton,  Pa.,  where  the  street 
railway  power  station  is  located  just  at  the  foot  of  a  gigantic 
pile  of  culm,  refuse  from  the  neighboring  coal  mines,  so  that 
the  fireman  could  almost  climb  up  the  side  of  the  pile  and 
kick  the  fuel  under  the  boilers.  Under  such  circumstances, 

IT  161 


!62  THE    ELECTRIC    RAILWAY. 

especially  as  the  culm  is  secured  at  a  nominal  price,  the  cost 
of  fuel  is  almost  negligible.  Ordinarily,  however,  one  must 
depend  on  the  railroads  for  the  transportation  of  coal,  and 
hence  it  is  most  desirable  to  place  the  station  close  beside  a, 
railroad  track,  even  if  the  site  be  rendered  somewhat  more 
expensive  by  so  doing.  If  the  coal  has  to  be  carted  at  all,  a 
few  hundred  yards  more  or  less  distance  makes  very  little 
difference,  as  the  expense  is  largely  in  the  handling. 

Aside  from  fuel,  water  is  the  next  prime  necessity  to  be 
considered ;  and  it  goes  without  saying  that  if  a  site  can  be 
found  close  both  to  railroad  tracks  and  water  of  suitable 
quality  for  use  in  the  boilers  the  station  should  be  placed 
there,  even  if  at  a  considerable  distance  from  the  point  that 
would  be  indicated  by  consideration  of  the  line  alone.  In 
small  stations,  where  condensing  engines  are  not  to  be  em- 
ployed, the  matter  of  water  supply  becomes  somewhat  less 
important,  but  still  deserves  careful  examination.  If  water 
for  condensation  is  required  it  is  almost  imperative  to  get 
within  pumping  distance  of  a  plentiful  supply. 

In  locating  a  railway  power  station,  then,  the  first  thing" 
to  be  considered  is  nearness  to  the  supply  of  fuel,  and,  after 
that,  central  position  with  reference  to  the  line  and  availa- 
bility of  water. 

In  finally  determining  the  best  location  for  a  station  noth- 
ing but  actual  expense  estimates  will  enable  a  decision  to  be 
formed.  If  the  station  is  placed  far  away  from  the  center  of 
the  system  additional  copper  will  be  needed  in  the  line  to 
compensate  for  its  increased  distance,  but  to  offset  this  there 
may  be  the  gain  that  comes  from  cheaper  fuel  and  water.  In 
two  places,  one  convenient  to  the  supply  of  fuel,  the  other 
in  the  center  of  the  system,  there  will  probably  also  be 
differences  in  the  cost  of  real  estate. 

If  to  obtain  cheap  fuel  it  becomes  necessary  to  move  the 
station  so  far  from  the  center  of  the  system  that  the  interest 
on  the  increased  amount  of  copper  necessary  is  greater  than 
the  probable  annual  saving  in  fuel,  it  is  sufficiently  obvious 
that  it  will  not  pay  to  put  the  station  near  the  fuel  supply. 
The  relative  cost  of  real  estate  in  the  two  places  must  also 
be  taken  into  consideration ;  it  often  happens,  however,  that 


THE    STATION.  163 

a  position  at  some  point  near  a  railway  track,  where  cheap 
fuel  can  be  obtained,  is  also  a  location  where  real  estate  is 
not  unreasonably  expensive ;  while  the  center  of  the  system 
is  quite  likely  to  be  near  the  center  of  the  town,  where  land 
is  decidedly  costly.  In  choosing  between  two  possible  sites 
for  a  station  the  interest  on  real  estate  at  the  two  points 
should  be  considered,  as  well  as  the  interest  on  the  invest- 
ment in  copper  and  the  saving  of  coal.  A  few  rough  esti- 
mates will  show  the  more  economical  location.  In  the 
majority  of  cases  it  is  possible  to  get  near  coal  and  water 
without  getting  very  far  away  from  a  reasonably  central 
position  on  the  line,  but  now  and  then  the  question  becomes 
more  complicated-  and  recourse  must  be  taken  to  the  estimates 
just  mentioned. 

It  may  here  be  well  to  take  some  notice  of  the  use  of  water 
power.  It  is  not  under  all  circumstances  that  the  water- 
wheel  can  successfully  compete  with  the  steam  engine,  and 
the  question  should  be  determined  on  its  merits  in  each  par- 
ticular case  where  it  arises.  Estimates  should  be  made  of  the 
cost  of  installation  of  the  wheels  and  the  necessary  water 
ways  to  feed  them ;  the  cost  of  water  rights  should  be  found, 
and  the  approximate  amount  of  extra  loss  entailed  by  the 
generally  more  inconvenient  location  of  the  power  station. 

With  these  data  can  be  compared  the  probable  cost  of  coal 
necessary  for  producin  y  the  equivalent  horse-power,  and  the 
difference  in  investment  if  engines  are  to  be  employed.  The 
constancy  of  the  water  power  must  be  carefully  considered, 
with  reference  both  to  its  failure  at  a  critical  moment  and 
the  regularity  of  supply  necessary  to  give  the  wheels  sufficient 
margin  of  po\ver  for  good  regulation. 

It  must  be  borne  in  mind  that,  particularly  in  a  small  sta- 
tion where  the  variations  in  load  are  excessive,  water  is  by 
no  means  easy  to  regulate ;  and  the  greatest  care  should  be 
•exercised  in  the  installation  for  the  purpose  of  securing  uni- 
formity of  speed,  even  under  the  large  changes  of  output 
required.  This  irregular  output,  that  is  a  prominent  charac- 
teristic of  most  electric-railway  plants,  in  contradistinction 
from  every  other  sort  of  installation,  is  a  thing  which  should 
l>e  most  watchfully  considered  in  designing  future  stations. 


164 


THE    ELECTRIC    RAILWAY. 


It  is  hard,  even  by  diagrams,  to  give  any  adequate  idea  of 
the  changes  of  load  to  which  a  small  railway  plant  may  be 
subjected;  they  are  extraordinarily  great  and  exceedingly 
sudden.  Fig.  88,  which  is  a  fac-simile  of  a  record  for  ten 
minutes  on  a  recording  ammeter,  may  give  some  faint  idea 
of  the  condition  of  things.  It  will  be  seen  that  at  one  point 
the  output  jumped  from  zero  to  150  horse-power  and  back  in- 
side of  a  single  minute,  and  during  the  latter  five  minutes 
shown  in  the  diagram  there  were  no  less  than  twenty-five 
sudden  variations  of  50  to  100  horse-power,  each  taking  place 


£25 
FIG.  SB—DIAGRAM  OF  VARIATION  OF  CURRENT  IN  AN  ELECTRIC  RAILWAY  SYSTEM. 

within  a  few  seconds.  The  road  from  which  this  record  was 
obtained  is  about  four  miles  in  length,  and  was  operating: 
seven  cars  at  the  time  of  the  test. 

The  effect  of  such  a  state  of  affairs  is  twofold :  First,  the 
regulating  power  of  the  machinery  is  taxed  to  its  utmost, 
and  even  the  best  governed  high-speed  engines  do  not 

•espond  quickly  enough  to  keep  the  voltage  on  the  line 
constant  under  such  circumstances,  while  water-wheels  are 
totally  unable  to  keep  pace  with  changes  so  sudden.  Second, 

wing  both  to  poor  governing  and  great  variations  in  actual 
ichanical  strain,  the  machinery,  whatever  it  may  be,  is  all 


THE    STATION.  165 

subjected  to  severe  and  unusual  tests  of  its  strength  and 
stability. 

It  therefore  becomes  necessary  that  in  a  railway  power 
station  the  foundations,  engines,  shafting  and  dynamos 
should  be  of  the  best  mechanical  construction.  The  use  of 
heavy  fly-wheels  on  the  engine  or  the  shaft  of  the  water- 
wheel  is  to  be  recommended,  especially  in  small  stations; 
and  all  engines  designed  for  this  class  of  work  should  be 
exceptionally  strong  and  solid  in  construction,  and  most 
securely  bolted  to  an  unusually  firm  foundation.  The  same 
is  true  of  all  shafting  that  is  to  be  employed,  and  the  dynamos 
should  be  fixed  in  position  as  solidly  as  possible.  On  extend- 
ed street  railway  systems,  running  a  considerable  number  of 
cars  over  a  comparatively  level  track,  the  variations  in  load 
are  of  course  much  less,  and  consequently  such  extraordinary 
care  in  station  construction  becomes  unnecessary.  But  in 
these,  as  in  all  similar  cases,  it  is  best  to  err  on  the  side  of 
safety. 

Not  only  should  this  condition  of  variable  load  that  we 
have  mentioned  affect  the  mechanical  design  of  the  station, 
but,  to  a  certain  extent,  it  should  also  modify  the  general 
arrangement  of  the  plant  with  reference  to  the  location  oi 
the  various  portions  of  the  machinery.  Especially  is  this 
true  in  small  stations  where  only  one  engineer  is  em- 
ployed. 

It  is  most  desirable,  under  such  circumstances,  so  to  place 
the  engines,  switchboard  and  dynamos  that  they  can  be 
readily  seen  and  their  performance  watched  from  a  single 
point.  If,  for  example,  lightning  enters  a  station,  and  one 
of  the  dynamos  begins  to  blaze  at  the  commutator,  the  en- 
gineer ought  to  be  able  to  reach  the  switches  without  rushing 
the  length  of  the  dynamo  room  and  around  various  portions 
of  the  machinery.  If  a  fuse  blows,  it  ought  to  be  in  such  a 
position  as  to  be  readily  noticed  without  going  around  a 
corner  to  look  for  it.  This  condition  of  easy  accessibility  is 
not  difficult  to  fulfill,  but  is  sometimes  neglected.  Wherever 
the  entire  equipment  is  subjected  to  often  repeated  and 
severe  strains  particular  care  should  be  observed  in  getting 
all  the  safety  devices  and  switches  where  they  can  be  easily 


!66  THE    ELECTRIC    RAILWAY. 

reached.  In  large  stations  where  several  men  are  constantly 
employed  the  necessity  does  not  become  so  imperative. 

With  respect  to  the  general  design  of  a  railway  power  sta- 
tion marked  differences  must  necessarily  exist  between  small 
and  large  installations ;  of  course  this  is  true  of  electric-light 
stations  as  well,  but  to  a  far  less  extent,  for  the  same  reasons 
that  we  have  endeavored  to  impress  on  the  reader  in  the 
preceding  paragraphs. 

The  differences  that  should  exist  between  plants  of  various 
sizes  will  be  pointed  out  later,  by  giving  the  sketches  of  three 
designs  for  widely  divergent  station  capacities.  As  a  general 
principle,  it  is  safe  to  say  that  the  subdivision  of  power 
should  be  carried  rather  further  in  railway  plants  than  is 
ordinary  in  the  construction  of  an  electric-light  installation, 
for  the  reason  that  the  various  component  parts  generally 
being  subjected  to  far  greater  strains,  and  worked  at  a  point 
much  further  from  their  normal  capacity,  both  security 
against  accidents  and  general  economy  demand  rather 
smaller 'units  of  power  than  in  cases  where  the  load  is,  rela- 
tively speaking,  uniform  and  somewhere  near  the  full 
capacity  of  the  machinery.  A  fundamental  law  of  economy 
in  installations  of  any  kind  is  to  work  at  all  times  as  near 
the  full  capacity  of  the  machines  employed  as  considerations 
of  safety  will  permit.  Dynamos  and  engines  are  both  de- 
signed to  carry  their  normal  rated  loads  economically  and 
continuously,  and  while  in  most  power  stations  for  railway 
work  the  great  variations  require  a  somewhat  larger  factor 
of  safety  between  the  normal  and  maximum  load  than  in  the 
case  of  electric-light  work,  the  same  broad  idea  must  govern 
the  arrangement  of  the  plans  for  either. 

In  beginning  the  task  of  designing  a  railway  power  sta- 
tion, the  first  problem  is  to  decide  on  the  amount  of  power 
to  be  required,  both  for  present  needs  and  future  exigencies. 
Neglect  of  looking  forward  to  the  possibilities  of  a  few  years 
hence  has  caused  inconvenience  in  many  an  electrical  instal- 
lation. On  the  other  hand,  construction  for  the  distant  period 
when  traffic  may  be  several  times  its  present  amount  is  cer- 
tain to  produce  an  inefficient  station. 

The  best  policy  is  to  build  at  first  fully  up  to  the  immediate 


THE    STATION.  167 

capacity  anticipated,  leaving  the  design  of  the  station  in  such 
form  that  additional  engines  and  dynamos  can  be  installed 
whenever  needed.  If  a  fairly  good  estimate  is  made  for  the 
initial  requirements  the  plant  can  be  increased  at  a  rate 
quite  sufficient  to  keep  pace  with  any  probable  demands.  It 
is  worth  noticing,  too,  that  if  the  number  of  cars  on  a  given 
line  is  doubled  the  maximum  capacity  of  the  plant  is  not 
increased  in  anything  like  the  same  ratio,  unless  in  cases 
where  very  large  numbers  of  cars  are  involved.  If,  for 
example,  an  electric  road  starts  with  twenty  cars  and  provides 
ample  equipment  for  them,  the  addition  of  twenty  more  will 
certainly  not  require  doubling  the  capacity  of  the  engines 
and  dynamos ;  for  as  the  number  of  cars  becomes  greater  the 
average  output  demanded  comes  more  nearly  to  approximate 
the  maximum  load,  without  very  much  increasing  the  latter. 

Where  only  three  or  four  cars  are  in  use  it  is  quite  possible 
that  all  the  motors  may  be  making  severe  demands  upon  the 
station  at  the  same  time;  for  example,  two  cars  may  be  on 
heavy  grades  at  the  moment  that  another  is  starting,  but 
with  forty  or  fifty  cars  the  varying  outputs  of  the  several 
motors  tend  to  balance  each  other,  and  it  is  safe  to  assume 
that,  even  with  a  ten-car  line,  at  no  time  will  all  the  mo- 
tors be  worked  simultaneously  up  to  their  full  capacity. 

So,  in  deciding  on  the  proper  capacity  for  the  plant  to  be 
constructed,  a  very  important  factor  is  not  only  the  size  of 
the  road,  but  its  size  with  reference  to  the  maximum  output 
that  the  conditions  of  service  will  require. 

Not  only  do  these  conditions  go  far  to  determine  the  proper 
capacity  of  the  various  prime  movers  employed,  but,  in  the 
case  of  steam  engines  at  least,  they  afford  good  reasons  for 
selecting  one  or  another  type  of  machine.  As  has  already 
been  mentioned,  in  the  chapter  on  prime  movers,  various 
forms  of  valve  gear  for  steam  engines  permit  of  very  different 
ranges  of  cut-off;  for  example,  some  of  the  automatic  high- 
speed machines  in  frequent  use  to-day  allow  the  steam,  when 
necessary,  to  follow  the  piston  throughout  nearly  the  full 
stroke,  while,  as  a  rule,  the  Corliss  valve  gear — than  which 
there  is  nothing  more  perfect  as  regards  the  results  obtained 
when  working  under  favorable  conditions — usually  permits 


!6S  THE   ELECTRIC    RAILWAY. 

a  range  of  cut-off  corresponding  to  only  about  two-fifths  of 
a  whole  stroke. 

It  therefore  goes  without  saying  that  when  extreme  varia- 
tions in  load  are  to  be  expected,  as  is  the  case  in  compara- 
tively small  roads,  the  use  of  the  Corliss  engine  would  entail 
a  cylinder  big  enough  to  supply  the  maximum  output — often 
several  times  the  average  output — working  at  a  cut-off  of 
about  two-fifths  the  stroke.  This,  as  has  been  mentioned  in 
the  chapter  on  prime  movers  before  referred  to,  virtually 
compels  working,  on  the  average,  at  a  cut-off  too  short  for 
anything  like  good  efficiency.  To  certain  types  of  compound 
engines  the  same  considerations  apply,  although  it  should  be 
said  that,  as  a  rule,  these  machines,  particularly  when  used 
condensing,  stand  underloading  rather  better  than  simple 
engines.  In  the  case  of  very  small  roads,  the  choice  is  lim- 
ited to  high-speed  engines  with  a  wide  range  of  cut-off ;  of 
these  the  types  on  the  market  are  almost  too  numerous  to 
mention,  and  most  of  them  give  excellent  performances.  As 
the  size  of  the  road  increases  and  the  ratio  between  maxi- 
mum and  mean  loads  approaches  unity,  a  point  will  be 
reached  where  it  will  become  possible  to  employ  economi- 
cally large  compound  engines,  with  Corliss  or  equivalent  valve 
gear.  Condensation,  even  in  small  engines  of  all  classes, 
should  be  practiced  wherever  water  is  available,  unless  fuel 
is  extremely  cheap. 

With  very  large  stations,  triple,  and  even  quadruple,  ex- 
pansion engines  are  coming  into  use  and  do  admirable  work. 
It  is  hardly  probable  in  any  practical  electric  road,  however, 
that  so  good  economy  can  be  obtained  with  these  complex 
machines  as  is  usual  when  they  are  employed  for  other  pur- 
poses where  the  load  is  far  more  regular. 

Some  striking  examples  of  this  have  been  brought  to  the 
authors'  attention ;  in  one  case  a  triple-expansion  engine  of 
an  excellent  modern  type  was  put  into  use  in  the  power  sta- 
tion of  a  comparatively  small  road,  with  the  idea  that  great 
economy  of  fuel  would  be  obtained;  the  actual  result  was 
very  disappointing,  for  by  careful  tests  it  appeared  that  the 
electrical  horse-power  hour,  instead  of  being  obtained  by 
the  use  of  about  two  and  one-half  pounds  of  coal,  or  less, 


THE    STATION.  169 

actually  required  between  six  and  seven  pounds — a  result  no 
better  than  could  have  been  reached  by  using  a  far  less 
expensive  and  complicated  simple,  non-condensing,  high- 
speed engine,  of  the  kind  generally  employed  for  such  serv- 
ice. It  was  one  of  the  cases  where  neglect  of  properly 
considering  the  question  of  load  led  to  unhappy  results. 

If  we  were,  then,  to  attempt  to  obtain  a  general  idea  of 
the  kind  of  engine  suitable  for  any  given  station,  we  must 
be  able  to  predict,  roughly  at  least,  the  ratio  between  maxi- 
mum and  mean  loads.  In  a  general  way,  whenever  the 
former  is  three  times,  of  thereabouts,  the  latter,  nothing  will 
give  better  results  than  a  plain,  solid,  high-speed  engine 
with  a  heavy  fly-wheel ;  with  the  maximum  load  about  double 
the  mean  load,  the  various  forms  of  Corliss  and  similar  en- 
gines come  into  play  with  excellent  results ;  and  where  the 
load  ratio  approaches  even  more  nearly  to  unity  and  the 
road  is  of  considerable  size,  requiring  500  horse-power  or 
over,  it  is  probable  that  the  best  results  will  be  obtained  by 
using  triple-expansion  engines.  These  are  only  approximate 
figures,  but  they  at  least  give  an  idea  of  the  circumstances 
that  should  cause  the  selection  of  one  sort  of  engine  rather 
than  another. 

Perhaps  the  best  insight  into  the  methods  to  be  followed 
in  laying  out  a  power  station  for  an  electric  road  may  be 
obtained  by  considering  plans  for  several  plants  of  particular 
sizes  and  the  special  circumstances  that  lead  to  their  adoption 
in  each  case.  We  shall  select,  then,  three  specimen  cases, 
and  investigate  them  in  considerable  detail.  First,  we  shall 
take  up  a  five-car  road  of  average  character ;  second,  one  with 
twenty-five  cars  or  thereabouts,  and  finally,  a  large  city  sys- 
tem with  one  hundred  cars  in  regular  service.  These  three 
cases  may  fairly  serve  as  examples  by  which  to  show  the 
various  conditions  that  have  to  be  met  in  designing  a  per- 
manent and  efficient  power  station. 

Let  us  suppose,  in  the  first  place,  that  the  problem  before 
us  is  to  install  in  a  town  of  ten  or  fifteen  thousand  inhabitants 
a  small  electric  road,  not,  as  will  be  the  case  in  larger  places, 
for  the  purpose  of  enabling  the  business  streets  of  the  city  to 
be  reached  from  the  suburbs,  but  to  facilitate  transit  from  one 


I/O 


THE    ELECTRIC    RAILWAY. 


part  of  the  town  to  another.  The  track  will  probably  be  less 
than  five  miles  in  length  and  usually  a  single  track  with 
turnouts. 

The  grades,  of  course,  are  liable  to  be  of  almost  any 
amount,  depending  on  the  configuration  of  the  country;  but, 
as  a  rule,  no  continuous  grades  of  more  than  six  or  seven 
per  cent,  are  likely  to  be  encountered,  although  there  may 
be  short  pitches  of  slightly  heavier  gradient— nothing,  how- 
ever, of  sufficient  length  to  require  particular  consideration. 
On  most  small  roads  of  this  sort  the  service  is  rather  infre- 
quent, the  cars  being  run  on  from  fifteen  to  thirty  minutes' 
headway,  and  five  cars  will  generally  be  enough  to  give 
ample  accommodations.  Such  a  road  is  typical  of  a  large 
portion  of  those  now  in  existence  and  of  very  many  of  those 
to  be  built  in  the  future;  for  the  electric  road,  from  its  com- 
paratively small  cost  of  installation,  can  be  utilized  in  a  vast 
number  of  places  Avhere  otherwise  there  would  be  no  street 
railroads  at  all,  or  at  most  miserable  horse  affairs,  giving 
very  poor  service. 

Starting,  then,  with  the  assumption  of  our  five  cars  oper- 
ating over  not  more  than  five  miles  of  track  and  over  grades 
of  only  moderate  severity,  the  question  that  must  be  consid- 
ered is  the  character  and  size  of  the  power  plant  required. 
In  such  situations  the  cars  employed  are,  for  the  most  part, 
sixteen  or  eighteen  foot  bodies  on  six-foot  wheel  bases; 
these  have  sufficient  capacity  for  the  work,  can  be  employed 
to  draw  trailers  if  necessary,  and  are  of  reasonable  weight. 
The  same  considerations  that  in  Chapter  IV.  were  used  to 
determine  the  distribution  of  copper  will  serve  fairly  well  for 
determining  the  capacity  of  the  power  station. 

It  may  be  useful  here  to  give  a  brief  table  showing  approx- 
imately the  power  required  to  drive  a  sixteen-foot  car  weigh- 
ing, with  its  equipment  and  a  moderate  load  of  passengers, 
eight  tons,  up  grades  from  one  to  ten  per  cent.,  at  the  uniform 
rate  of  eight  miles  per  hour,  which  is  not  very  far  from  being 
a  fair  average.  On  very  light  grades  the  determining  factor 
of  the  power  required  is  the  condition  of  the  track,  and  on 
very  well  laid  track  the  so-called  "  coefficient  of  traction  " 
should  be  fifteen  or  sixteen  pounds  per  ton;  on  ordinary 


THE    STATION.  171 

street-car  track  it  is  more  frequently  twenty,  and  rises  from 
that  figure  to  twenty-five,  thirty,  and  in  some  cases  even  to 
forty  pounds  per  ton ;  twenty  pounds  is  quite  nearly  correct 
for  the  average  conditions,  and  the  table  is  founded  on  that 
assumption. 

Per  cent,  grade. 


Power  at  wheels. 

Per  cent   grade. 

Power  at  wheels. 

3-5 

6 

22.5 

6.5 

7 

25.5 

9.5                                8 

28.5 

13.0 

Q 

32 

16 

IO 

35 

19 

4 

5 

This  table  gives  the  mechanical  power  required  at  the  car 
axle,  to  the  nearest  half  horse-power. 

The  average  commercial  efficiency  of  the  motors  is  here 
taken  at  the  figure  that  is  to-day  true  for  most  of  those  in 
use,  of  about  sixty  per  cent.  To  a  very  considerable  extent 
grades  compensate  themselves,  so  that  their  effect  on  the 
average  power  required  is  not  by  any  means  so  great  as  upon 
the  variations  in  the  power.  Heavy  grades  mean  a  widely 
fluctuating  maximum  load,  but  they  increase  the  average 
daily  output  by  only  a  comparatively  moderate  amount. 

With  the  ordinary  car  equipment  of  two  fifteen  horse-power 
motors,  and  the  usual  speeds,  from  eight  to  twelve  miles  per 
hour,  experience  has  shown  that  five  to  six  electrical  horse- 
power per  car  is  necessary  on  nearly  level  track.  Ordinary 
grades  upon  the  road  will  not,  in  general,  increase  this 
amount  greatly;  they  will,  however,  cause  more  or  less 
extended  periods  of  exceedingly  heavy  output,  rising  to 
twenty-five  or  thirty  horse-power  for  each  car  on  the  grade. 

On  large  roads,  where  these  times  of  abnormal  output  are 
infrequent,  one  can  safely  count  on  the  figure  just  given  for 
the  power  required  per  car;  under  such  circumstances  about 
ten  indicated  horse-power,  at  the  station,  per  car  will  there- 
fore prove  quite  sufficient.  On  a  road  like  the  one  we  are 
contemplating,  with,  possibly,  severe  grades  and  only  five  cars 
in  operation,  it  may  easily  happen,  for  example,  that  a  couple 
of  the  cars  may  be  simultaneously  upon  the  grade  and  a  third 
starting  under  somewhat  unfavorable  circumstances.  The 
amount  of  current  ordinarily  taken  in  starting  a  car  is  momen- 


jj2  THE    ELECTRIC    RAILWAY. 

tarily  more  than  fifty  amperes,  which  at  the  ordinary  voltage 
corresponds  to  about  2  5,  ooo  watts;  we  therefore  might  have  80 
or  90  horse-power  demanded  for  a  minute  or  twro,  and  a 
longer  call  for  power  of  50  to  75  horse-power,  depending  of 
course  on  the  length  of  the  grades  which  are  to  be  sur- 
mounted. 

In  towns  where  there  are  small  roads  such  as  we  are  con- 
sidering, it  frequently  happens,  too,  that  inordinate  demands 
for  power  are  made  on  the  occasion  of  a  somewhat  infrequent 
theatre  night,  a  political  demonstration,  a  base-ball  game  at 
some  point  far  out  on  the  line,  and  other  public  gatherings. 
This  usually  means  bunching  three  or  four  heavily  loaded 
cars,  sometimes  all  the  cars  on  the  line,  at  one  point,  and 
starting  them  out  within  a  minute  or  two  of  each  other;  for 
a  small  road  is  dependent  for  its  revenue  largely  on  its 
willingness  and  ability  to  accommodate  just  such  unusual 
demands. 

It  would  therefore  probably  happen  that  on  our  five-car 
road  there  would  be  times  when  the  output  would  have  to 
reach  nearly  or  quite  100  horse-power  for  a  few  minutes  at  a 
time,  although  it  would  be  strange  if  the  average  electrical 
horse-power  required  throughout  the  day  should  exceed  30. 
The  reader  will  therefore  readily  understand  that,  under  the 
circumstances  supposed,  a  far  greater  margin  of  power  is 
required  than  in  case  of  a  larger  system. 

In  a  comparatively  small  place  it  is  fortunately  not  difficult 
to  obtain  a  favorable  location  for  a  power  station,  and  the 
expense  of  securing  a  site  convenient  to  fuel  is  generally  not 
great.  Our  station  should  be  located  as  centrally  as  feasible, 
and  close  alongside  a  railway  track  or  wharf,  where  coal  can 
be  easily  obtained.  It  is  highly  desirable,  even  in  so  small 
an  installation,  to  have  a  spare  engine  and  dynamo,  although 
it  frequently  is  impracticable ;  it  may  be  laid  down,  however, 
as  a  rule  of  fundamental  importance,  that  a  road  should. never 
be  trusted  to  a  single  dynamo  for  continuous  running,  and 
even  if  the  total  output  required  be  small,  two  dynamos  should 
be  employed  ;  for  nothing  damages  the  reputation  of  a  street- 
railway  system  more  permanently  than  a  breakdown  that 
requires  the  suspension  of  traffic  for  a  day  or  so,  and  such 


THE    STATION.  173 

breakdowns  are  sooner  or  later  bound  to  occur  where  only  a 
single  dynamo  is  used.  Railway  generators  are  peculiarly 
susceptible  to  injury  from  lightning,  and  for  this,  if  no  other 
reason,  the  above  precaution  is  necessary.  For  our  specimen 
five-car  road,  a  proper  outfit  of  dynamos  would  be  two  of 
about  40,000  watts  rated  capacity  each;  this  means  an  ability 
to  supply  100  electrical  horse-power,  or  more  if  necessary, 
and  sufficient  capacity  in  either  dynamo  to  keep  up  a  toler- 
able service  on  the  road  if  its  mate  should  unfortunately  be 
disabled. 

As  regards  the  type  of  engine  that  should  be  employed 
there  is  little  room  for  dispute,  for  the  only  thing  that  would 
answer  the  purpose  properly  is  a  high-speed  simple  engine, 
belted  direct  to  the  generators,  and  having  as  much  weight 
in  frame  and  fly-wheel  and  as  wide  a  range  of  cut-off  as  is 
practicable.  If  it  can  be  run  condensing,  so  much  the  better, 
as  in  most  cases  of  employing  steam  engines.  Its  capacity 
should  be,  approximately,  80  indicated  horse-power  at  one- 
quarter  stroke  cut-off  and  90  or  100  pounds  steam  pressure. 

It  will  be  observed  that  the  rated  capacity  of  the  engine  of 
this  plant  is  much  less  than  that  of  the  dynamos;  and  this 
is  the  correct  arrangement,  for,  as  will  be  shown  in  the 
chapter  on  efficiency,  a  dynamo  can  be  run  at  half  its  nom- 
inal output  without  serious  loss  of  efficiency,  while  under 
similar  circumstances  an  engine  not  only  loses  from  its 
friction  becoming  a  large  portion  of  the  total  output,  but  the 
machine  per  sc  becomes  less  economical  of  steam.  Occasion- 
ally compound  engines  of  as  small  size  as  that  mentioned  are 
used,  but  they  are  not  to  be  recommended  for  such  a  small 
and  widely  varying  output,  as  the  increase  in  economy  of 
fuel  is  not  sufficient  to  counterbalance  the  increased  first  cost 
and  the  slighter  greater  complication  and  consequent  danger 
of  trivial  accidents,  which,  though  easily  repaired,  will,  where 
a  single  engine  is  employed,  cripple  the  entire  road. 

The  boilers  for  the  plant  should  be  quite  capable  of  supply- 
ing steam  for  100  horse-power  easily,  and  rather  more  if 
pushed  a  little.  Two  boilers  should  be  employed,  to  permit 
giving  one  of  them  careful  attention.  A  single  boiler  is 
undesirable  for  the  same  reason  as  a  single  dynamo.  It  is 


!74  THE    ELECTRIC    RAILWAY. 

even  better  to  have  two  boilers — either  of  them  sufficiently 
large  to  handle  the  plant  if  necessary — and  employ  them 
alternately;  this  principle,  which,  although  more  expensive 
in  first  cost,  is  cheaper  in  the  long  run,  will  be  dwelt  upon 
in  speaking  of  the  arrangement  to  be  employed  in  large 
stations. 

We  have,  therefore,  for  this  first  specimen  station,  an 
equipment  consisting  of  two  4<D,ooo-watt  dynamos,  one  80 
horse-power  high-speed,  simple  engine  belted  directly  to 
them,  and  two  boilers  of  about  50  nominal  horse-power  each. 

As  to  the  type  of  boiler  to  be  employed,  it  is  largely  a 
matter  of  taste  and  convenience ;  probably,  for  general  use, 
nothing  is  much  more  satisfactory  than  the  plain  tubular  or 
return  tube  types,  well  set  and  provided  with  ample  furnace 
capacity. 

Excellent  results  are  obtained  from  the  water-tube  form  of 
boiler,  of  which  there  are  now  a  number  of  meritorious  pat- 
terns. We  should  hesitate,  however,  to  advocate  their  use  to 
the  exclusion  of  the  regular  tubular  boiler. 

In  any  case  it  must  be  remembered  that  the  intrinsic 
differences  in  boilers  are  vastly  less  than  the  individual 
differences  introduced  by  general  care  and  skillful  firing. 
Boilers  should  be  periodically  cleaned  and  overhauled  in  the 
most  thorough  manner;  hence  the  necessity  for  a  spare 
boiler,  which  will  permit  this  to  be  properly  done  without 
suspending  operations,  unless  in  part.  It  should  be  remem- 
bered always,  then,  that  a  plain  boiler  with  a  skillful  fireman 
will  give  better  results  than  the  most  expensive  and  elab- 
orate form  of  patented  boiler  with  a  poor  fireman. 

A  very  convenient  arrangement  for  such  a  small  station 
is  shown  in  Fig.  89.  Everything  is  under  a  single  roof  and 
on  one  floor,  with  a  stack  at  one  side;  the  floor  space  is 
divided  into  two  nearly  equal  portions,  one  devoted  to  the 
boilers  and  coal  bins,  the  other  to  the  engine  and  aynamos. 
The  engine  is  placed  at  the  end  of  the  dynamo  room  close 
to  the  boilers,  and  belted  directly  to  the  two  generators  with 
slightly  different  lengths  of  belt,  so  as  to  render  both  ma- 
chines more  accessible. 

The  switchboard  is  placed  as  shown,  on  the  wall  close  to 


THE    STATION.  175 

both  engines  and  dynamos,  so  that  the  engineer,  sitting  in 
any  convenient  spot,  can  watch  the  operation  of  the  entire 
plant  and  be  almost  within  reaching  distance  of  the  appa- 
ratus. Of  course  circumstances  will  necessarily  vary  the 
plans  of  the  station,  but  the  example  given  is  convenient 
in  its  arrangement. 

As  regards  material,   the  station   should  preferably  be  a 
substantial  brick  structure ,  if  necessary,  however,  a  frame 


FIG.  89.— ARRANGEMENT  OF  POWER  STATION  FOR  A  FIVE-CAR  ROAD. 

building  answers  the  purpose  fairly  well.  If,  as  is  sometimes 
the  case  in  either  construction,  an  iron  roof  is  used,  it  should 
be  carefully  sheathed,  either  by  roofing  felt  or  by  a  wooden 
ceiling  at  the  eaves;  if  this  precaution  be  not  taken,  there 
is  likely  to  be  constant  trouble  from  moisture  condensing  on 
the  machines  under  variations  of  temperature,  a  contingency 
which  is  carefully  to  be  avoided.  For  a  permanent  station, 
a  brick  building  and  substantial  chimney  should  uniformly 
be  erected. 


!~6  THE    ELECTRIC    RAILWAY. 

The  foundations  are  a  matter  of  prime  importance ;  both 
engines  and  dynamos  should  be  given  a  most  solid  bed  con- 
structed of  rubble  and  cement,  or  brickwork,  as  convenience 
dictates,  but  far  more  substantial  than  would  be  employed  in 
supporting  ordinary  machinery.  The  dynamos  ought  to  be 
carefully  insulated,  the  wooden  base  on  which  they  are  usu- 
ally placed  being  generally  sufficient  for  this,  provided  proper 
foundations  are  employed.  The  interior  fittings  and  switch- 
board ought  to  be  the  subject  of  careful,  thorough  construc- 
tion :  for  no  money  is  saved  by  cheap  and  hasty  work  about 
a  station.  Lightning  arresters  and  the  like  should  be  given 
non -combustible  bases  of  a  size  large  enough  to  avoid  danger 
of  any  woodwork  catching  fire  in  case  of  accident.  The  usual 
insurance  rules  for  electric  installations  will  serve  as  a  suffi- 
cient guide  for  putting  up  the  subsidiary  apparatus. 

Passing  now  to  the  next  case  to  be  discussed,  let  us  con- 
sider a  road  employing  in  the  neighborhood  of  twenty-five 
cars  for  regular  service,  and  situated  in  a  thriving  city  of  a 
size  sufficient  to  give  a  reasonably  heavy  traffic.  Let  the 
grades  be  about  as  in  the  former  case  and  the  cars  be  of 
similar  type. 

For  roads  operating  from  five  to  twenty-five  cars,  probably 
no  better  arrangement  could  be  devised  than  an  amplification 
of  the  system  just  suggested,  employing  as  the  system  in- 
creases two  or  three  engines  and  four  or  six  dynamos,  and 
allowing  from  twelve  to  eighteen  normal  indicated  horse- 
power at  the  engines,  according  to  the  size  of  the  system 
and  the  severity  of  grades.  Compound  engines  maybe  used 
with  great  advantage  for  machines  of  100  horse-power  and 
upward,  especially  if  it  is  possible  to  obtain  water  for  con- 
densation. As  for  a  twenty-five-car  road,  it  is  on  debatable 
ground,  where  a  question  necessarily  arises  between  the 
slight  economy  to  be  gained  by  direct  belting  and  the  great 
convenience  of  being  able  to  operate  any  and  all  the  dynamos 
from  either  of  the  engines.  At  about  the  same  size  of  plant, 
too,  the  low-speed  engine  begins  to  come  into  play. 

For  a  road  of  the  size  we  are  considering,  an  allowance  of  ten 
or  twelve  indicated  horse-power  per  car  would  nearly  always 
be  sufficient,  and  a  proper  equipment  for  twenty-five  cars  will 


THE    STATION. 


consist  of  four  6o-kilowatt  dynamos.  When  long  cars  or 
snow  sweepers  are  used,  each  should  be  reckoned  as  equal  to 
two  ordinary  cars.  It  is  probably  preferable  to  have  recourse 
to  a  countershaft,  and  this  should  be  situated  at  one  end  of 
the  dynamo  room  and  on  very  substantial  foundations.  The 
dynamos,  arranged  as  shown  in  Fig.  90,  should  each  be  driven 
from  a  pulley  provided  with  a  friction  clutch,  enabling  any 
of  the  machines  to  be  employed.  The  shaft  itself  should  be 


FIG.  90.— ARRANGEMENT  OF  POWER  STATION  FOR  A  25-CAR  ROAD. 

divided  into  two  sections,  connected  to  each  other  and  to  the 
engines  by  friction  clutches. 

With  an  installation  of  this  size  two  engines  should  always 
be  employed,  belted  direct  to  driving  pulleys  at  the  ends  of 
the  line  shaft ;  these  engines  should  be  of  similar  or  identical 
pattern,  and  may  be  either  simple  or  compound,  as  the  con- 
ditions of  fuel  expense  may  dictate.  Corliss  or  similar 
low-speed  engines  may  very  well  be  used  under  these  cir- 
cumstances, as,  except  in  certain  cases,  the  fluctuations  of 
load  are  not  likely  to  be  great  enough  to  put  such  an  engine 
at  any  considerable  disadvantage.  With  slow-speed  engines, 
either  simple  or  compound,  a  rated  capacity  of  150  horse- 
power is  desirable  for  each.  If  high-speed  engines  having  a 


i;8  THE    ELECTRIC    RAILWAY. 

wide  range  of  cut-off  are  employed,  125  horse-power  nominal 
capacity  for  each  will  probably  be  sufficient.  The  boilers 
should  be  three  or  four  in  number,  aggregating  about  300 
horse-power.  Fig.  90  shows  the  general  arrangement  of  such 
a  station  as  has  just  been  described.  In  operating  it,  a  little 
judgment  will  enable  excellent  results  to  be  attained.  Dur- 
ing a  large  part  of  the  day  one  engine  operating  two,  or  pos- 
sibly three,  of  the  dynamos  will  handle  the  load  easily  and. 
evenly;  in  the  morning  and  the  evening,  and  at  times  when 
especially  heavy  work  is  required,  all  the  dynamos  and  both 
engines  can  be  put  into  use.  Under  these  circumstances, 
repairs  on  the  engines  or  dynamos  are  easily  carried  out 
without  interfering  seriously  with  the  regular  service  of  the 
road.  If  compound  engines  are  used,  they  should  be  worked 
condensing  if  possible.  The  cross-compound  type  is  prob- 
ably preferable,  in  the  matter  of  ease  of  repairs  and  accessi- 
bility, to  the  tandem  patterns,  although  some  of  the  latter 
do  excellent  work.  The  fly-wheels  in  any  case  should  be  of 
unusual  weight — at  least  50  per  cent,  heavier  than  would  be 
employed  in  driving  ordinary  machinery.  For  roads  oper- 
ating over  twenty-five  cars,  an  amplification  of  the  plans  just 
given  works  admirably,  the  size  of  engines  and  dynamos 
being  increased  to  meet  the  larger  output  required. 

Taking  up  the  case  of  a  one-hundred-car  road,  something 
of  the  same  line  of  equipment  may  be  followed,  but  the 
dynamo  units  should  of  course  be  larger.  For  one  hundred 
cars  six  iso-kilowatt  machines  are  desirable,  allowing  a 
sufficient  surplus  of  power  to  reserve  one  dynamo  as  spare 
equipment.  The  same  arrangement  of  the  line  shaft  may  be 
advantageously  followed.  It  is  probably  advisable,  however, 
to  divide  it  into  three  sections  instead  of  two,  providing,  as 
before,  friction  clutches  for  each  d/namo  pulley  and  each 
driving  pulley.  Usually  two  or  tnree  ngines  may  be  used, 
preferably  three,  as  this  number  enables  i  better  adjustment 
of  the  load  and  permits  one  of  the  engines  10  be  tnrown  out 
of  use  for  repairs  without  causing  serious  inconvenience. 
For  so  large  a  plant,  triple-expansion  condensing  engines 
are  very  strongly  to  be  recommended ;  three  of  400  nominal 
horse-power  each  would  answer  the  purpose  admirably. 


THE   STATION. 


1/9 


Under  these  conditions  the  mean  load  can  be  kept  reasonably 
near  the  full  output  of  the  machines  in  use  all  the  time. 

Except  for  a  few  hours  each  day,  two  engines  will  do  the 
work  and  do  it  well,  and  one  dynamo  could  be,  and  should 
be,  reserved  to  be  thrown  in  only  when  it  is  absolutely 
necessary.  Slow-speed  engines,  with  Corliss  or  equivalent 
valve  gear,  are  in  their  element  in  an  installation  of  this  size ; 
and  all  the  great  advantage  of  their  unusual  efficiency  can  be 


FIG.  91.— ARRANGEMENT  OF  POWER  STATION  FOR  A  IOO-CAR  ROAD. 


enjoyed.  The  boiler  capacity,  aggregating  say  1,200  horse- 
power, should  always  be  divided  into  five  or  six  units,  so 
that  the  boilers  can  be  thoroughly  overhauled,  one  at  a  time, 
without  causing  any  special  inconvenience.  A  good  arrange- 
ment for  a  one-hundred-car  station  is  shown  in  Fig.  91. 

In  a  road  of  this  size  it  is  decidedly  advantageous  to  employ 
some  double-truck  long  cars,  with  two  motors  of  20  horse- 
power or  thereabouts ;  and  these  should  be  counted  as  the 


!80  THE    ELECTRIC    RAILWAY. 

equivalent  of  two  standard  cars  in  making  up  the  total  equip- 
ment. On  small  roads  such  cars  are  not  advisable,  as  they 
are  very  heavy  and  would  have  to  be  run  very  lightly  loaded 
a  large  part  of  the  time ;  but  as  the  size  of  the  system  and 
the  traffic  increase,  their  use  becomes  desirable,  as  in  every 
case  where  high  speed  is  to  be  attempted. 

In  unusually  large  electric-railway  installations,  operating 
several  hundred  cars,  it  is  often  advisable  to  employ  an 
arrangement  radically  different  from  the  one  just  mentioned 

that  is,  very  large  low-speed  dynamos,  coupled  or  belted 

directly  to  triple-expansion  engines,  forming  a  combination 
plant  quite  similar  to  that  now  generally  used  for  ship  light- 
ing, but  on  an  enormously  larger  scale.  The  advantages  to 
be  found  in  this  description  of  plant  are,  first,  a  saving  of 
perhaps  five  per  cent.,  owing  to  dispensing  with  the  counter- 
shaft and  belting;  and,  second,  compactness,  an  advantage 
not  to  be  despised  in  large  cities,  where  land  is  exceedingly 
expensive.  The  disadvantages  are  those  that  always  attend 
the  use  of  a  comparatively  small  number  of  machines ;  for, 
in  case  of  accident,  a  considerable  fraction  of  the  plant  might 
be  rendered  for  the  time  being  unfit  for  use,  thus  interrupt- 
ing the  service.  Unless  the  size  of  the  installation  is  so- 
great  that  five  or  six  300  or  400  horse-power  dynamos  are 
required,  the  arrangement  of  countershaft  that  has  just  been 
described  will  generally  be  found  preferable,  for  it  enables 
any  or  all  of  the  dynamos  to  be  run  from  any  engine  or 
combination  of  engines.  This  secures  not  only  immunity 
against  breakdown,  but  also  enables  the  load  to  be  readily 
adjusted  so  as  to  keep  the  engines  and  dynamos  actually  in 
use  nearly  up  to  their  full  output,  and  consequently  operating 
at  their  best  efficiency. 

A  number  of  our  present  electric  roads  have  employed 
for  service  aggregating  as  high  as  one  hundred  cars  merely 
an  exaggeration  of  the  plans  just  laid  down  for  the  roads  of 
the  smallest  size,  some  few  designing  engineers  having  car- 
ried the  subdivision  of  power  to  a  very  needless  extreme.  If 
the  conditions  of  high  average  load  are  fulfilled,  such  sys- 
tems as  those  just  mentioned  may- work  very  economically; 
but  it  is  believed  that  with  equal  care  the  designs  we  have 


THE    STATION.  l8l 

shown  will  produce  somewhat  better  results  in  economy  of 
fuel,  continuity  of  service,  and  small  repair  bills.  As  regards 
the  subdivision  of  power,  one  general  rule  may  safely  be 
laid  down,  deviation  from  which  is  very  likely  to  lead  to  high 
running  expenses  or  disastrous  uncertainty  of  service ;  it  is 
this:  The  number  of  power  units  should  be  just  such  that  the  dis- 
abling of  one  of  them  ivill  not  interfere  with  the  successful  operation 
of  the  system.  It  will  very  seldom  happen  that  more  than  a 
single  unit,  composed  of  an  engine  and  dynamo,  or  engine 
and  two  dynamos,  will  be  disabled  at  the  same  time.  Owing 
to  the  fact  that  accidents  are  rather  more  likely  to  happen  to 
dynamos  than  to  engines,  the  engine  units  may  be  larger 
than  the  dynamo  units.  In  very  small  plants  it  becomes 
necessary  sometimes  to  take  one's  chances  of  being  crippled 
by  an  accident,  btit  every  station  should  be  so  designed  that 
an  engine  or  dynamo  can  be  stopped  for  repairs  at  any  time, 
without  seriously  interfering  with  the  car  service. 

Since  writing  the  above,  there  has  appeared  a  very  valu- 
able statistical  article  by  Mr.  J.  S.  Badger*  on  the  operation 
of  electric  roads ;  and  from  this  we  cull  some  data  regarding 
station  operation  that  are  of  the  utmost  value  as  emphasizing 
the  general  principles  of  station  design  here  laid  down.  The 
very  best  performance  as  yet  recorded  for  an  electric-railway 
power  station  is  furnished  by  the  East  Cleveland  road — No. 
4  of  Mr.  Badger's  paper. 

The  station  equipment  consists  of  horizontal  return  tubular 
boilers  with  Murphy  furnaces,  furnishing  steam  at  100  pounds 
pressure  to  three  200  and  three  125  horse-power  Armington 
&  Sims  simple,  high-speed  engines,  belted  directly  to  Edison 
generators.  Of  these  there  are  six  No.  32  and  six  No.  16, 
the  former  being  of  80  kilowatts  and  the  latter  40  kilowatts 
rated  capacity. 

The  road  is  in  general  level,  with,  however,  one  five  per 
cent,  grade  400  feet  in  length ;  seventy  motor  cars  and 
seventy  trailers  are  on  the  average  in  daily  use.  One 
electrical  horse-power  is  obtained  for  every  five  pounds  of 
slack  or  four  pounds  of  nut  coal  consumed,  the  evaporation 
being  7^  pounds  of  water  per  pound  of  slack.  The  cars  run 

*  The  Electrical  World-.  October  31,  1891. 


!82  THE    ELECTRIC    RAILWAY. 

on  an  average  91.1  miles  per  day  each,  and  the  consumption 
of  fuel  per  car  mile  is  4. 3  pounds  of  slack  or  a  corresponding 
proportional  quantity  of  nut.  This  is  a  very  excellent  exam- 
ple of  correct  proportioning  of  station  capacity  to  work, 
although  even  a  better  performance  would  have  be'en  at- 
tained had  compound  condensing  engines  been  used. 

It  will  be  noted  that  the  aggregate  capacity  of  the  dynamos 
at  the  full  rated  load  was  980  horse-power,  a  little  less  than 
half  the  rated  capacity  of  the  motors,  thus  following  closely 
the  proportion  we  have  suggested  elsewhere.  Further,  the 
engines  were  of  a  trifle  less  capacity  than  the  dynamos,  975 
horse-power,  and  at  full  output  the  dynamos  would  give  \2l/2 
electrical  horse-power  for  each  motor  car.  Trailers  were 
steadily  used,  a  practice  the  advantage  of  which  has  often 
been  pointed  out,  so  that  the  actual  electrical  horse-power 
provided  per  car  at  the  rated  output  of  the  dynamos  would 
probably  be  about  eight — at  all  events,  somewhat  less  than 
10;  and  this  also  is  in  accordance  with  the  estimates  we  have 
given. 

In  the  actual  operation  of  the  station,  the  coal  required 
was  but  five  pounds  of  slack  for  every  electrical  horse-power 
hour,  which  corresponds  very  well  with  the  evaporation  given, 
showing  a  consumption  of  nearly  35  pounds  of  water  per 
indicated  horse-power,  a  thoroughly  consistent  figure,  and 
one  not  by  any  means  unusually  great  for  high-speed  engines 
running  under  variable  load. 

Had  compound  condensing  engines  been  substituted  for 
the  simple  machines,  preserving  practically  the  same  propor- 
tion of  engines  to  dynamos,  even  this  excellent  performance 
could  have  been  improved;  since  five  pounds  of  slack,  at  an 
evaporation  of  7^,  was  required  per  electrical  horse-power 
hour — certainly  much  more  than  would  m have  been  needed 
with  large  condensing  engines. 

Were  any  evidence  needed  to  show  that  the  good  result 
was  due  to  proper  proportioning  of  the  station,  it  can  be 
readily  found  from  the  details  of  Mr.  Badger's  road  Xo.  2. 
In  this  case  the  engine  power  aggregated  675  horse-power, 
while  the  dynamos  were  five  in  number,  of  80  kilowatts  each, 
total  about  535  horse-power;  the  engines  were  all  high-speed 


THE    STATION.  183 

machines  of  standard  make,  running  on  a  steam  pressure 
of  80  pounds ;  the  grades  of  the  road  were  decidedly  heavier 
than  in  the  case  previously  mentioned,  the  steepest  being  gl/2 
per  cent,  and  about  400  feet  in  total  length.  Sixteen  motor 
cars  only  were  in  regular  use,  and  although  the  company 
had  trail  cars,  they  were  seldom  used.  The  full  dynamo 
capacity  was  a  trifle  over  35  horse-power  per  car,  and  the 
fuel  used  was  nut  and  slack,  of  which  the  consumption  was 
1:0  less  than  1 1  pounds  per  car  mile  as  against  4.3  on  the  East 
Cleveland  road.  Although  the  conditions  mentioned  were 
somewhat  more  severe  in  road  No.  2,  so  far  as  economy  is 
concerned,  the  direful  effect  of  the  preposterously  large  en- 
gine and  dynamo  capacity  is  only  too  evident  in  the  enor- 
mous consumption  of  fuel. 

It  will  be  noticed,  in  planning  the  model  stations,  that  in 
every  case  the  whole  installation  has  been  shown  on  a  single 
floor,  and  that  the  ground  floor;  and  whenever  it  is  practi- 
cable this  is  the  best  arrangement,  because  thereby  immunity 
from  vibration  and  ready  access  to  all  parts  of  the  plant  are 
secured.  Sometimes,  though  rarely,  in  city  stations,  ground 
space  becomes  so  expensive  that  it  must  be  economized  so 
far  as  possible ;  it  then  becomes  necessary  either  to  use  the 
direct-coupled  dynamos  just  mentioned,  or  to  place  the  engines 
on  the  ground  floor  and  belt  upward  to  the  dynamos,  either 
directly  or  through  the  medium  of  a  line  shaft.  This  simple 
procedure  is  likely  to  cause  a  great  deal  of  trouble  from  hot 
bearings.  A  number  of  such  plants  are  running,  usually  for 
electric-light  apparatus,  and  in  many  cases  they  will  be  found 
in  operation  with  the  caps  removed  from  the  bearings  and 
convenient  means  at  hand  for  cooling  the  journals  with  water. 
In  any  such  case  the  dynamos  should  be  provided  with  a 
substantial  support  directly  under  them,  and  should  not  be 
trusted  to  the  supporting  floor  beams.  It  is  far  better  to  use 
the  direct  coupled  engine  and  dynamos  where  circumstances 
compel  contracted  quarters  for  the  station. 

A  word  may  well  be  said  here  on  the  subject  of  belting. 
It  is  advisable  to  use  leather  belting  of  the  very  best  quality, 
special  attention  being  paid  in  selecting  it  to  closeness  of 
grain  and  pliability.  There  are  now  in  the  market  a  consid- 


!84  THE   ELECTRIC    RAILWAY. 

erable  number  of  patented  beltings  of  various  descriptions — 
canvas  belting,  perforated  belting,  and  link  belts  of  different 
kinds;  these  various  sorts  are  frequently  used,  and,  as  a  rule, 
give  satisfaction ;  but  we  have  yet  to  learn  that  they  are  pro- 
ductive of  better  general  results  than  first  quality  plain  leather 
belting  kept  in  good  order 

With  regard  to  the  minor  arrangements  of  a  station,  there 
are  many  details  which  can  hardly  find  a  proper  place  in  this 
volume,  unless  it  be  sufficient  merely  to  suggest  them.  The 
switchboard  in  any  station  should  be  placed  where  it  is  very 
easily  accessible  and  in  plain  view  of  the  dynamos ;  the  other 
apparatus  should  be  easily  visible  from  the  regulating  devices, 
and  these  latter  should  be  grouped  together  for  convenience 
and  placed  where  they  can  be  reached  in  a  moment  if  any- 
thing happens.  Plenty  of  room  should  be  allowed  for 
switches  and  cut-outs,  and  both  should  be  of  the  most  sub- 
stantial description.  Whether  the  cut-outs  are  magnetic  or 
merely  fuses,  they  should  be  looked  after  at  frequent  inter- 
vals and  kept  in  good  order,  and  never  should  be  set  to  act  at 
the  nominal  rated  capacity  of  the  dynamos.  It  is  an  unneces- 
sary refinement  of  cautiousness  and  will  result  in  stoppage  of 
the  cars  without  any  good  results,  for  any  well-constructed 
dynamo  will  carry  for  a  few  minutes  nearly  50  per  cent,  over 
its  rated  capacity  without  doing  any  damage  whatsoever. 

In  case,  for  example,  of  a  short  circuit  on  the  line*  it  is  far 
better  to  overload  the  plant  by  25  or  30  per  cent,  and  keep 
the  cars  running,  than  to  save  the  fuses  at  the  expense  of 
stoppage  of  traffic;  for  fuse  wire  is  cheap,  but  the  loss  of 
public  confidence  that  results  from  frequent  cessation  of  cur- 
rent on  a  line  is  a  very  serious  matter,  particularly  when  the 
railway  company  has  to  ask  any  favors  of  the  municipality. 
The  dynamo  itself  gives  plenty  of  warning  of  an  overload 
before  it  is  in  any  way  injured ;  and  a  judicious  and  watchful 
engineer  will  very  often  save  blocking  the  cars  by  keeping 
his  hand  on  the  switch  and  his  eye  on  the  ammeter.  Of 
course  it  should  be  remembered  that  with  a  large  station  a 
given  short  circuit  on  the  line  may  cause  no  serious  results, 
while  in  a  smaller  station  it  might  necessitate  cutting  out 
the  dynamos  to  save  the  armatures. 


THE    STATION.  1 8$ 

Every  station  should  be  equipped  with  a  good  set  of  testing- 
instruments,  consisting  of  a  standard  ammeter,  voltmeter, 
one  or  more  magnetos,  and  a  portable  testing  set  for  the 
measurement  of  resistance.  It  is  desirable  that  the  ammeter 
and  voltmeter  should  be  portable,  so  that  they  can  be  used 
on  the  cars  if  necessary ;  and  in  large  stations  special  instru- 
ments should  be  provided  for  this  purpose.  In  addition,  at 
least  one  engine  indicator  should  be  provided — better  still, 
two — and  for  stations  where  there  are  compound  or  triple- 
expansion  engines,  enough  to  use  simultaneously  on  each 
cylinder  of  a  given  engine.  The  expense  is  not  great,  and  the 
instrument  is  more  than  likely  to  save  many  times  its  cost  in 
fuel.  A  standard  steam  gauge  for  testing  the  gauges  in  the 
boiler  room  is  a  useful  addition  to  the  equipment,  also  some 
form  of  portable  tachometer  for  getting  the  speed  of  engines 
and  dynamos. 

It  is  worth  while  stating  something  here  about  lightning 
arresters.  Enough  has  been  said  in  the  chapter  on  motors 
to  give  some-idea  of  the  importance -of  providing  such  appa- 
ratus, but  everything  said  about  the  danger  to  motors  is 
thrice  true  of  dynamos.  A  railway  generator,  being  a  shunt 
or  compound  wound  machine  of  high  voltage,  is  peculiarly 
sensitive  to  the  attacks  of  lightning;  for  there  is  direct  com- 
munication between  the  line  and  the  armature,  and  a  lightning 
stroke  entering  the  station  is  very  likely  to  do  mischief. 

The  direct  damage  done  to  the  machine  by  the  lightning 
itself  is  usually  small,  and  a  powerful  stroke  is  not  at  all 
necessary  to  very  disastrous  results.  The  action  is  usually  as 
follows :  the  lightning  enters  the  station  and  reaches  the 
machine  in  sufficient  amount  to  puncture  the  insulation  of 
the  armature;  the  current  follows  the  spark,  and  the  machine 
promptly  destroys  itself.  The  extent  of  the  damage  may 
go  all  the  way  from  a  few  wires  melted  off  to  an  almost 
complete  destruction  of  the  armature  windings  and  the 
commutator. 

It  therefore  becomes  necessary  in  protecting  railway  ma- 
chines against  lightning  to  ward  off  if  possible  every  particle 
of  the  discharge.  Ordinary  lightning  arresters,  the  function 
of  which  is  simply  to  provide  an  alternative  course  to  earth, 


lS6  THE    ELECTRIC    RAILWAY. 

are  practically  useless  under  these  circumstances ;  it  is  not 
sufficient  that  the  lightning  may  choose  between  going 
through  the  machine  and  to  ground  through  the  arresters ;  it 
must  if  possible  be  compelled  to  take  the  latter  course.  It  is 
a  well-known  fact  that  both  arc  dynamos  and  railway  motors, 
in  fact,  all  series-wound  machines,  are  much  less  liable  to 
damage  from  lightning  than  shunt  or  compound  wound 
machines ;  this  is  owing  to  the  fact  that  before  any  lightning 
can  enter  the  armature  from  the  line  it  must  pass  through 
the  series  magnetizing  coils  of  the  machine,  which  possess 
quite  high  self-induction  and  choke  back  the  entering  dis- 
charge in  a  more  or  less  efficient  manner. 

Bearing  this  in  mind,  the  use  of  powerful  impedance  coils 
situated  between  the  lightning  arresters  and  dynamos,  as 


FIG.  92.— ARRANGEMENT  OF  IMPEDANCE  COIL  WITH  LIGHTNING  ARRESTER. 

shown  in  Fig.  92 ,  is  strongly  to  be  recommended ;  by  offering 
a  powerful  resistance  to  the  passage  of  a  sudden  discharge 
through  them  in  the  direction  of  the  armature,  they  are 
likely  to  drive  the  lightning  to  ground  and  save  the  machines. 
Without  such  assistance  it  is  quite  possible  for  the  lightning 
to  jump  to  ground  through  the  lightning  arrester,,  and  also 
partially  to  discharge  into  the  dynamo  and  destroy  it.  It  is 
quite  impossible  to  give  explicit  advice  as  to  the  necessary 
power  of  the  impedance  coil  required,  but  one  having  ap- 
proximately the  magnetic  dimensions  of  the  field  magnets  of 
the  motors  will  probably  answer  the  purpose. 

As   lightning    usually    enters    a    station    from    the    line 
rather  than  from  the  ground,  it  may  be  a  useful  precaution 


THE    STATION.  l8/ 

so  to  connect  the  series  coils  on  compound-wound  dynamos 
that  they  shall  be  between  the  armature  and  the  line,  and  by 
their  considerable  impedance  help  protect  the  former.* 

On  account  of  lightning,  if  for  no  other  reason,  a  railway 
dynamo  ought  to  be  carefully  insulated  from  the  ground ;  for 
under  these  circumstances  the  armature  runs  less  risk,  inas- 
much as  the  lightning  discharge  is  then  not  so  likely  to 
jump  to  and  through  the  armature  core.  Aside  from  this, 
the  frame  ought  not  to  be  grounded,  on  the  score  of  safety 
to  the  men  who  are  handling  the  dynamo.  As  to  the  pro- 
tection of  the  station  itself  from  lightning,  it  may  be  well 
to  suggest  that  in  case  an  iron  roof  is  used,  as  is  not  infre- 
quent, grounding  it  at  one  or  more  points  converts  it  into  a 
most  efficient  lightning  rod.  (See,  further,  Appendix  E). 

In  the  boiler  room  accessory  apparatus  should  not  be  for- 
gotten. In  large  stations,  mechanical  stokers  are  a  highly 
desirable  addition  to  the  plant,  as  they  enable  an  economical 
use  of  grades  of  coal  that  will  much  reduce  the  fuel  bill.. 
Separators  and  feed- water  heaters  should  be  regularly  em- 
ployed, unless  the  arrangement  of  the  boilers  with  reference 
to  the  engines  is  such  as  to  render  the  former  unnecessary. 
For  feeding  the  boilers,  duplicate  or  triplicate  means  should 
be  provided,  so  that  no  easily  supposable  series  of  accidents 
can  prevent  the  proper  feeding  of  water.  If  condensing  en- 
gines are  used,  care  should  be  taken  to  have  the  supply  of 
water  for  condensation  ample ;  and  in  every  case  the  engineer 
should  be  watchful  both  of  the  quantity  and  quality  of  the 
water  for  the  boilers.  Where  good,  clear  river  or  pond 
water  can  be  obtained,  nothing  better  is  to  be  desired ;  where 
this  is  not  available  driven  wells  may  answer  the  purpose. 
If  one  is  compelled  to  depend  on  the  city  water  supply,  the 
bill  is  apt  to  be  unpleasantly  large,  particularly  if  condensa- 
tion is  to  be  attempted,  and  arrangements  should  be  made 
for  procuring  an  independent  supply  of  water. 

In  the  dynamo  room  there  are  divers  devices  that  may  be 
profitably  introduced.  One  of  these  is  a  permanent  traveling 
crane,  supplied  with  differential  tackle  of  sufficient  power  to 

*  This  proceeding  is  useless  where  the  series  coils  are  shunted  by  a  resistance. 


!88  THE    ELECTRIC    RAILWAY. 

handle  the  component  parts  of  any  of  the  dynamos  used. 
With  this  apparatus  the  replacing  of  an  armature  or  field 
becomes  a  very  simple  and  easy  matter,  while  without  it 
much  time  is  consumed  and  considerable  danger  of  injuring 
the  machinery  is  incurred.  It  is  advisable  to  fit  up  in  con- 
nection with  the  dynamo  room  a  little  workshop  where 
minor  repairs  can  be  executed ;  for  an  engineer  who  is  handy 
with  tools  can  oftentimes  save  his  company  a  good  deal  of 
money,  and  he  should  certainly  be  provided  with  a  sufficient 
kit  of  machinists'  tools  to  encourage  him  in  their  use.  Large 
stations  usually  should  have  a  repair  shop  connected  with 
them,  and  many  companies  even  go  so  far  as  to  rewind 
armatures — sometimes  making  an  excellent  job  and  saving 
a  very  considerable  amount  of  money  thereby. 

In  constructing  a  station  of  any  size  whatever,  room  should 
be  left  for  an  increase  of  plant— not  to  be  put  in,  however, 
until  it  is  needed.  A  few  feet  extra  length  in  line  shafting 
.will  easily  permit  the  introduction  of  a  couple  of  extra 
dynamos  in  a  station  of  some  size,  and  in  a  very  small  sta- 
tion ground  space  is  usually  cheap  enough  to  permit  leaving 
room  for  an  additional  engine  and  pair  of  dynamos  when  they 
shall  become  necessary. 

As  regards  the  general  care  of  dynamos,  little  special  in- 
struction need  here  be  given.  As  railway  dynamos  run  for 
the  most  part  at  five  or  six  hundred  volts,  they  are  somewhat 
more  liable  to  short  circuits,  both  in  armature  and  commu- 
tator, than  are  ordinary  incandescent  or  arc  machines.  As  a 
result  of  this,  they  should  be  kept  scrupulously  clean ;  the 
commutators  should  be  cleaned  with  great  care,  especially  if 
carbon  brushes  are  used ;  the  brushes  should  be  kept  nicely 
trimmed,  and,  in  fact,  extra  precautions  should  be  taken 
throughout  the  station. 

The  variations  in  load  on  railway  machines  are  apt,  as  we 
have  many  times  before  stated,  to  be  very  violent  and  very 
sudden,  so  that  there  may  be  more  sparking  at  the  commu- 
tator than  is  usual  in  other  dynamos.  A  sharp  lookout 
should  be  kept  for  this,  and  the  brushes  shifted  whenever 
necessary. 

The  carbon  brush  has  come  into  very  considerable  use, 


THE    STATION.  189 

and  a  word  regarding  its  employment  is  appropriate.* 
Where  carbon  brushes  are  to  be  used  a  little  extra  work 
should  be  spe'nt  on  the  commutator,  in  keeping  it  perfectly 
clean,  otherwise  it  is  likely  to  heat  from  short  circuits  caused 
by  carbon  dust,  and  frequently  exhibits  the  symptom  of  mi- 
nute sparks  flashing  from  under  the  brushes  from  segment 
to  segment.  When  carbon  brushes  are  working  at  their  best 
they  simply  impart  a  grayish  tinge  to  the  entire  commutator, 
without  causing  either  heating  or  flashing.  If  there  is  a  no- 
ticeably unequal  blackening  of  the  commutator  it  is  likely 
that  trouble  will  follow,  and  the  commutator  should  be  rubbed 
clean  at  once. 

Dynamos  of  different  makes  and  sizes  cannot  always  be 
run  in  parallel  on  a  railway  circuit,  for  the  reason  that  they 
may  be  magnetically  unlike,  and  will  not  then  respond  with 
«qual  promptness  to  magnetic  changes;  therefore,  when  the 
load  varies,  as  it  may  often  and  violently,  the  machines  will 
not  respond  equally,  and  the  load  will  be  unevenly  distrib- 
uted, causing  unnecessary  strains  on  one  or  more  of  the 
machines.  It  is  likewise  very  undesirable  to  run  in  parallel 
•dynamos  driven  by  engines  of  different  makes  and  speeds, 
for  when  a  sudden  load  is  thrown  upon  the  system  the  engine 
governors  will  not  respond  with  equal  promptitude,  throwing 
the  system  out  of  balance  and  causing  certain  machines  to 
<Io  far  more  than  their  share  of  the  work .  Engine  makers  will 
often  point  with  pride  to  the  fact  that  their  machines  are  so 
well  governed  that  they  will  not  vary  in  speed  more  than  one 
•or  two  revolutions  per  minute,  when  running  empty  and 
when  running  loaded.  This  boast  is  sometimes  true,  but 
nevertheless  the  speed  of  these  very  engines  at  the  time  of 
throwing  on  the  load  may  momentarily  vary  10  or  even  20 
per  cent. 

A  slow-running  engine  necessarily  governs  with  less 
promptitude  than  a  high-speed  engine,  and  in  most  cases  the 


*  Probably  the  handiest  way  of  trimming  a  carbon  brush  is  to  strap  a  piece  of  sand- 
paper, face  out,  around  the  commutator  after  the  current  has  been  shut  off  for  the  night, 
and  drop  the  brushes  into  the  brush-holders,  letting  the  machine  run  slowly  until  the 
sandpaper  has  smoothed  off  the  end  of  the  brushes  into  the  proper  form.  A  supply  of 
brushes  thus  prepared  can  be  put  in  whenever  necessary,  and  will  run  smoothly  and 
quietly  from  the  very  moment  they  touch  the  commutator.  Take  care  not  to  let  the  car- 
ibon  dust  get  to  the  commutator  connections,  as  it  may  make  trouble. 


190 


THE    ELECTRIC    RAILWAY. 


practiced  eye  can  detect  at  the  moment  of  sudden  load  a 
very  marked  slowing  down  of  the  fly-wheel,  unless  it  be  of 
unusual  weight.  It  is  for  this  reason  that  heavy  fly-wheels 
are  so  strongly  recommended,  for  they  enable  the  engine  to 
tide  over  the  period  of  sudden  load  with  greater  ease  than 
would  otherwise  be  the  case;  it  must  not  be  forgotten,  how- 
ever, that  no  engine  governor  in  general  use  to-day  begins 
to  act  until  the  speed  has  actually  begun  to  fall,  so  the  fly- 
wheel is  of  particular  service  only  in  helping  the  engine 
over  very  sudden  changes. 

It  is  worth  remembering  that  from  the  high  voltage  of 
railway  dynamos  and  the  consequent  violence  of  any  short 
circuits  that  occur,  the  machines  are  subject  to  serious  acci- 
dents under  circumstances  which  would  lead  to  but  trivial 
results  in  low-voltage  stations.  It  is  therefore  advisable  to 
cut  out  the  machine  as  soon  as  it  shows  signs  of  trouble  that 
cannot  be  immediately  removed  by  caring  for  the  commutator 
a  little.  The  insulation  should  be  frequently  tested  after 
shutting  down  for  the  night,  and  every  precaution  taken  to 
avoid  die  beginning  of  difficulties,  for  when  once  begun  they 
grow  with  extraordinary  rapidity. 

In  case  of  a  short  circuit  on  the  line  the  engineer  should 
stand  by  the  machines,  watching  them  and  the  ammeter,  and 
t  ready  to  cut  them  out  if  it  becomes  necessary ;  it  is  a  good, 
safe  rule,  however,  to  hold  on  until  the  fuses  go,  in  order  to 
avoid  shutting  down  the  line.  With  copper  brushes  a  short 
circuit  on  the  line  was  frequently  followed  by  a  very  consid- 
erable injury  to  the  commutator,  but  now  that  the  carbon 
brush  has  come  into  general  use  the  machines  will  stand  a 
pretty  severe  ground  on  the  trolley  wire  without  danger. 

Finally,  the  engineer  of  a  power  station  should  co-operate 
with  the  superintendent  of  the  road  in  keeping  watch  of  the 
performance  of  the  entire  system.  The  engines  should  be 
indicated  at  least  once  a  day,  and  the  ammeter  and  voltmeter 
readings  should  be  taken  simultaneously  with  the  indications. 
The  amount  and  time  of  abnormally  large  currents,  the 
occurrence  and  severity  of  short  circuits  in  particular,  ought 
to  be  noted  in  an  engineer's  log-book,  as  well  as  the  effect  of 
any  unusual  service  occurring  on  the  line,  such  as  the  em- 


THE   STATION.  19! 

ployment  of  a  snow  plow,  the  effect  of  trailers,  if  they  are 
used,  and  the  result  of  any  particularly  heavy  service.  If 
possible,  the  amount  of  coal  burned  each  day  should  be  noted, 
and  also  a  rough  check  kept  of  the  amount  of  water  used. . 
The  former  amount  can  sometimes  very  conveniently  be 
ascertained,  if  not  every  day,  at  least  occasionally,  by  taking 
a  time  when  the  coal  pile  can  be  easily  cleared  out  and  meas- 
uring in  barrels  the  coal  used. 

If,  as  is  usually  the  case,  particularly  in  stations  of  any 
size,  feed-pumps  are  used  for  supplying  the  boilers,  the 
weight  of  water  delivered  per  stroke  of  pump  can  be  very 
readily  determined;  and  by  attaching  to  the  pump  a  simple 
stroke  counter  like  the  registering  mechanism  of  a  gas  meter, 
the  total  amount  of  water  pumped  per  day  may  be  at  once 
found;  then,  by  bringing  the  water  at  the  close  of  the  day's 
work  in  each  boiler  back  to  the  point  where  it  was  at  starting 
up  in  the  morning,  the  total  amount  of  water  evaporated  per 
day  can  be  roughly  ascertained.  By  taking  the  coal  con- 
sumption and  water  consumption  in  connection  with  the 
indications  of  the  engine  and  the  simultaneous  volt  and 
ammeter  readings,  the  whole  performance  of  the  station  can 
be  periodically  determined  without  much  trouble,  and  sources 
of  loss  detected  and  estimated. 

An  engineer's  log-book  in  which  can  be  entered  the  data 
mentioned  is  highly  desirable,  and  in  Appendix  C  is  given 
a  convenient  form  of  page  for  noting  these  various  facts. 
It  is  filled  in  so  as  to  show  in  a  general  way  its  application. 
The  report  can  be  and  should  be  made  as  full  as  practicable, 
and  in  case  of  special  tests  it  is  only  necessary  to  fill  the  log- 
book more  completely  than  is  shown  in  the  example,  taking 
indicator  and  ammeter  readings  at  more  frequent  intervals. 
Now  and  then,  at  least,  voltmeter  and  ammeter  readings,  at 
intervals  of  a  few  minutes  throughout  the  time  of  running, 
should  be  made;  and,  in  fact,  the  engineer  of  the  power  sta- 
tion ought  to  take  pride  in  knowing  all  the  details  of  the 
performance  of  the  machines,  for  not  only  are  these  of  im- 
portance in  helping  him  to  operate  the  station  successfully, 
but  they  possess  a  money  value  to  the  company  that  employs 
him. 


I92  THE    ELECTRIC    RAILWAY. 

In  closing  this  somewhat  brief  consideration  of  railway 
power  stations,  we  can  do  no  better  than  to  impress  again  on 
the  mind  of  the  reader  the  necessity  for  solid  and  substantial 
work  throughout,  the  importance  of  using  only  the  most 
carefully  made  engines  of  extra  weight  and  strength,  and 
the  prime  necessity  of  so  arranging  the  installation  that  it 
can  be  kept  loaded  as 'nearly  as  possible  to  its  full  capacity 
throughout  the  hours  of  running.  And  finally,  the  last  place 
to  economize  is  in  the  engineer's  wages ;  for  a  cheap  engineer 
can  do  enough  mischief  in  one  day,  through  sheer  ignorance, 
to  eat  up  the  dividends  for  an  entire  year.  It  requires  an 
unusually  intelligent  and  skillful  man  to  handle  a  railway 
power  station  properly,  and  such  an  one  must  be  obtained, 
even  at  a  cost  considerably  above  that  familiar  to  those  whose 
experience  has  been  in  other  lines. 

HINTS  FOR  THE  CARE  OF  RAILWAY  POWER  STATIONS. 

It  may  be  well  to  append  here,  for  the  benefit  of  those 
who  have  to  do  with  the  running  of  stations,  a  brief  series 
of  hints  on  the  special  care  that  must  be  given  to  station 
apparatus ;  although  what  has  previously  been  said  is  quite 
sufficient  for  those  who  are  already  somewhat  familiar  with 
the  operation  of  dynamos  such  as  are  used  for  lighting. 

BOILERS. 

To  begin  at  the  boiler  room,  it  is  almost  unnecessary  to 
state  that  scale  is  the  fireman's  worst  enemy.  Boiler  scale 
is  the  natural  and  logical  result  of  insufficient  attention  to 
the  boilers.  All  water  holds  in  solution  a  certain  amount  of 
mineral  matter,  varying  from  the  merest  traces — next  to  none 
at  all — to  quite  a  perceptible  fraction  of  an  ounce  per  gallon, 
in  mineral  waters.  Hard  water,  so  called,  is  that  containing 
an  unusual  proportion  of  mineral  matter,  most  frequently 
salts  of  lime. 

During  the  process  of  evaporation  that  goes  on  in  the 
boiler  all  this  material  is  left  behind,  and  unless  the  boiler  is 
periodically  cleaned  out,  a  deposit,  calcareous  in  nature  and 
sometimes  almost  as  hard  as  stone,  will  be  formed  wherever 
the  water  touches  the  iron  shell  or  tubes  of  the  boiler. 


THE    STATION.  193 

In  addition,  there  is  likely  to  be  a  certain  amount  of  sus- 
pended matter  in  water — particularly  river  water — which  is 
.added  to  the  general  collection  of  foreign  matter  anql  is  likely 
to  coat  the  interior  of  the  boiler  with  mud.  We  have  seen 
boiler  scale  a  quarter  of  an  inch  thick  and  nearly  as  hard  as 
flint  taken  from  the  boilers  used  in  an  electric-light  station ; 
and,  in  fact,  it  is  only  too  common  to  find  scale  allowed  to 
accumulate  through  carelessness,  although  seldom  to  so  great 
an  extent. 

The  result  is  not  only  to  diminish  very  much  the  evapora- 
tive power  of  the  boiler,  but  to  expose  the  iron,  unshielded 
by  circulation  of  water  from  the  effects  of  direct  heating,  in 
such  a  way  as  to  rapidly  deteriorate  it  and  very  likely  to 
cause  a  boiler  explosion.  The  remedy  for  scale  is  to  period- 
ically clean  out  the  boilers  thoroughly  and  carefully,  and  to 
use  from  time  to  time  suitable  scale  preventers,  which  usually 
act  mechanically  by  hindering  the  scale  from  sticking  to 
the  iron.  A  large  number  of  these  are  in  use,  and  perhaps 
the  simplest  of  any  is  crude  petroleum,  a  small  amount  of 
\vhich  is  placed  in  the  bottom  of  the  boiler  after  it  has  been 
thoroughly  cleaned  and  before  the  water  is  turned  on ;  as  the 
boiler  fills,  its  interior  is  coated  with  a  film  of  oil  which 
does  not  allow  the  hard  deposit  of  scale  to  cling. 

No  general  rule  can  be  laid  down  as  to  the  frequency  of 
boiler  cleaning  necessary,  for  it  depends  entirely  on  the 
quality  of  the  water  used.  A  very  little  experience  will 
enable  an  engineer,  under  any  particular  circumstances,  to 
tell  in  what  quantity  deposit  is  forming  and  to  apply  thev 
proper  remedies  at  once.  As  mentioned  previously,  it  is 
best  in  installing  any  station  so  to  arrange  the  boiler  units 
that  one  or  more  can  be  thrown  out  of  use  and  thoroughly 
overhauled  without  interfering  seriously  with  the  working 
capacity  of  the  plant. 

It  should  be  the  engineer's  business  to  see  that  the  boiler- 
room  accessories  are  kept  in  proper  condition,  that  the  safety 
valve  is  all  right,  the  steam  gauge  registering  correctly,  the 
joints  tight,  and  the  pumps  in  working  order.  Duplicate 
means  should  invariably  be  provided  for  feeding  the  boilers, - 
for  one  of  the  most  serious  accidents  that  can  happen  is  the 
13 


I94  THE   ELECTRIC   RAILWAY. 

derangement  of  the  feeding  apparatus  so  that  water  cannot 
be  properly  fed  into  the  boilers.  If  injectors  of  the  Korting; 
or  any  other  type  are  employed,  a  steam  pump  also  should 
invariably  be  supplied;  and  even  if  but  seldom  used,  it 
should  be  tested  at  frequent  intervals  to  see  that  it  is  kept  in 
perfect  working  order  against  the  time,  which  must  inevitably 
come,  when  the  injector  gets  clogged  and  refuses  to  do  its 
duty.  All  steam  pipes  of  any  length  should  be  jacketed 
with  some  one  of  the  many  non-conducting  coatings  now  in 
use — magnesia,  asbestos,  mineral  wool,  or  the  like. 

ENGINES. 

With  respect  to  the  engines,  one  general  rule  may  be  laid 
down:  watch  their  performance  and  overhaul  them  at  the 
first  sign  of  trouble,  for  trouble  goes  on  from  bad  to  worse 
with  the  greatest  speed. 

A  well-made,  well-set  and  well-cared-for  engine  is  as  reli- 
able a  piece  of  machinery  as  the  ingenuity  of  man  has  yet 
devised,  but  if  ill-treated,  even  the  best  engine  will  go  on 
strike  with  extraordinary  persistence.  As  previously  men- 
tioned, the  foundations  for  engines  to  be  used  in  rail- 
way power  stations  should  be  extra  heavy,  and  the  engine 
itself  thoroughly  well  balanced.  There  should  be  very  little 
or  no  vibration  when  the  machine  is  running,  either  in  the 
engine  itself  or  in  the  steam  pipes.  If  the  engine  is  regu- 
larly indicated,  as  it  should  be,  the  valves  can  be  put  in  their 
proper  order  very  readily,  and  any  abnormal  features  about 
the  engine  noted  at  once.  Any  thumping,  rattling,  or  unu- 
sual irregularities  in  the  running  of  an  engine  should  be 
investigated  at  the  earliest  possible  moment  and  the  proper 
remedies  applied.  We  cannot  go  here  into  the  details  of 
running  an  engine,  but  can  only  give  these  general  cautions 
— rendered  all  the  more  necessary  in  railway  power  stations 
on  account  of  the  severe  strains  to  which  the  machinery  is 
sometimes  subjected. 

DYNAMOS. 

Some  general  hints  have  already  been  given  as  to  the 
proper  care  of  this  most  important  part  of  a  power-station 


THE   STATION.  195 

•equipment,  but  it  may  be  worth  while  to  go  somewhat  further 
into  detail,  and  to  give  an  idea  of  the  troubles  likely  to  be 
encountered  and  the  ways  of  reaching  them. 

The  list  of  faults  to  which  a  dynamo  may  be  subject  varies 
somewhat  with  the  size  and  character  of  the  machine ;  and 
what  applies  to  small  motors,  or  to  arc-light  dynamos,  is  not 
likely  to  apply  with  equal  force  to  railway  generators.  These 
latter  are  usually  very  well  made  and  efficient  machines,  as, 
indeed,  they  have  to  be  to  perform  the  severe  service  exacted 
from  them. 

As  regards  their  general  arrangement,  they  should  be  on 
firm  foundations,  readily  accessible,  and  provided  with  means 
for  loosening,  tightening,  and  aligning  the  belts.  First  of 
all,  they  should  be  kept  clean  and  dry,  and  usually,  if  well 
cared  for,  will  give  very  little  trouble.  However,  every 
dynamo  is  liable  sooner  or  later,  from  one  cause  or  another, 
to  operate  in  a  somewhat  unsatisfactory  manner.  Whatever 
the  cause  of  such  abnormal  performance  may  be,  it  must  be 
hunted  up  and  the  proper  remedy  applied  at  once. 

Speaking  in  a  general  way,  the  troubles  most  likely  to  be 
met  are  sparking,  heating  of  the  commutator,  armature,  or 
field  magnets,  heating  of  bearings,  and  failure  to  generate 
current  at  all;  this  last  is  unusual,  and  the  cause  may  be 
either  very  serious  or  very  trifling.  Of  course,  several  of 
these  "  bugs  "  often  develop  at  once,  as,  for  example,  a  pro- 
longed overload  is  likely  to  cause  sparking,  and  heating  of 
the  commutator,  armature  and  bearings. 

Taking,  however,  the  causes  mentioned  in  their  order,  we 
may  note  that  sparking  at  the  commutator  may  be  produced 
by  a  rather  wide  variety  of  causes.  The  commonest  one — 
so  common  as  to  hardly  require  comment — is  a  combination 
of  overload  and  wrong  position  of  the  brushes ;  the  former, 
a  glance  at  the  ammeter  will  tell,  and  in  addition  it  becomes 
manifest  by  overheating  of  the  armature,  severe  strains,  and 
sometimes  even  slipping  of  the  belt ;  the  latter  cause  can  be 
remedied  by  moving  the  rocker  arm  to  the  point  of  minimum 
sparking. 

In  the  earlier  railway  dynamos  it  was  quite  common  to  find 
a,  sudden  variation  of  load  requiring  a  considerable  change 


I96  THE    ELECTRIC    RAILWAY. 

in  the  position  of  the  brushes;  in  the  later  types,  however,, 
there  is  little  or  no  change  of  lead  with  load,  and  whether 
the  current  is  one  ampere  or  several  hundred,  the  brushes 
can  be  left  very  nearly  in  the  same  position.  If  you  chance 
to  be  operating  a  dynamo  where  the  non-sparking  position 
of  the  brushes  does  shift,  eternal  vigilance  is  the  only  way 
to  avoid  sparking  at  the  commutator. 

The  cause  of  sparking  just  mentioned  presupposes  that  the 
machine  is  in  good  condition,  but  it  is  not  altogether  uncom- 
mon to  find  sparking  produced  by  faults  either  in  the  com- 
mutator or  in  the  armature.  If  the  former  is  eccentric, 
irregularly  worn,  or  has  one  or  more  bars  loose  or  set  irreg- 
ularly with  respect  to  the  others,  sparking  is  sure  to  ensue; 
for  the  tension  on  the  brushes  is  irregular,  they  are  thrown 
into  vibration,  and  the  result  makes  itself  evident  at  once. 
An  examination  of  the  commutator  will  readily  detect  these 
defects.  A  rough  commutator  needs  no  description ;  and  if 
it  is  eccentric,  the  fact  can  be  readily  detected,  either  by  a 
visible  wabbling  or  by  holding  a  stick  lightly  against  its  sur- 
face, when  any  irregularity  in  motion  will  make  itself  appar- 
ent to  the  sense  of  touch.  Loose  or  irregular  bars  are  found 
with  equal  ease. 

In  these  days  of  carbon  brushes,  worn  commutators  are 
not  so  common  as  they  once  were ;  if  from  using  copper 
brushes  and  keeping  them  in  the  same  position  too  long  the 
commutator  should  become  untrue,  it  should  be  smoothed 
very  cautiously  with  a  fine  file,  or  very  fine  sand-paper — 
never  emery-paper — great  care  being  taken  to  brush  the 
minute  particles  of  metal  out  of  the  insulation  between  the 
commutator  segments  before  starting  up  the  machine.  In 
very  bad  cases,  a  thin  cut  taken  off  the  commutator  in  a  lathe 
will  remedy  the  difficulty ;  but  this  is  considerable  trouble, 
and  on  some  large  machines  a  tool  holder  is  arranged  to  be 
fitted  alongside  the  commutator,  so  as  to  turn  it  down  very 
easily  by  simply  running  at  low  speed  and  feeding  the  tool 
by  hand.  Similar  in  its  results  to  a  rough  commutator  is  a 
rough  brush.  A  little  examination  will  show  when  the  brush. 
is  irregularly  worn,  so  as  to  make  poor  contact,  and  if  so,  it 
should  be  trimmed  or  ground  down. 


THE    STATION. 


I97 


Sparking"  due  to  faults  in  the  armature  may  be  very  severe, 
but  is  almost  invariably  local  in  its  character ;  that  is,  affect- 
ing- only  a  few  of  the  commutator  segments.  This  peculiarity 
is  very  readily  noticeable,  and  such  an  effect  may  be  due 
either  to  a  short-circuited  coil  in  the  armature  or  a  broken 
coil,  either  one  of  which  will  produce  violent  sparking  at  the 
commutator  bar  or  bars  most  immediately  concerned  with 
that  particular  coil.  When  a  coil  is  short-circuited  it  heats 
very  violently,  may  burn  out  entirely,  and  is  quite  likely  to 
make  itself  obvious  by  a  smell  of  overheated  insulation.  On 
running  the  machine  slowly  the  current  may  show  pulsations, 
and  on  stopping,  running  the  fingers  over  the  armature  will 
generally  locate  the  short-circuited  coil  immediately  by  the 
heating,  particularly  if  one  is  guided  to  it  by  the  visible 
burning  at  the  edges  of  the  corresponding  commutator  seg- 
ments. 

Short  circuits  may  occasionally  be  produced  by  stray  par- 
ticles of  metal  getting  between  the  segments  of  the  commu- 
tator or  among  the  armature  connections.  Under  these 
circumstances  the  trouble  can  be  found  by  inspection  and 
easily  removed.  More  often  the  short  circuit  is  in  the  coils 
themselves,  and  may  usually  be  looked  for  at  the  head  of  the 
armature. 

Perhaps  the  most  elusive  of  all  faults  in  armatures  is  what 
may  best  be  described  as  a  flying  short  circuit — that  is,  a 
short  circuit  between  two  or  more  of  the  armature  coils  of 
such  a  character  that  it  does  not  appear  when  the  machine  is 
at  rest,  but  becomes  noticeable  as  soon  as  the  revolution  of 
the  armature,  by  centrifugal  force  or  magnetic  drag,  presses 
the  offending  \vires  together.  Under  these  conditions  the 
machine  may  fail  to  excite,  as  the  shunt  winding  is  completely 
short-circuited ;  there  will  be  little  or  no  heating,  because  of 
the  small  excitation  and  little  current  flowing  in  the  coils ; 
and  oftentimes  even  a  careful  measurement  of  the  resistance 
of  the  armature  coils  all  around  the  commutator  will  fail  to  dis- 
close the  trouble,  for  the  simple  reason  that  when  the  arma- 
ture stops  the  short  circuit  no  longer  exists.  Such  a  fault  is 
perhaps  best  found  by  separately  exciting  the  fields  and  then 
running  the  machine  rather  slowly,  when  all  the  character- 


j^8  THE    ELECTRIC    RAILWAY. 

istic  signs  of  short-circuited  coils  will  appear  and  can  be 
located  by  the  consequent  heating. 

If  there  is  a  broken  circuit  in  the  armature,  as  sometimes 
happens,  there  will  be  very  serious  flashing  at  the  commu- 
tator  localized  as  before — but  there  will  be  no  special  heat- 
ing of  a  single  coil.  The  defect  may  be  sought  at  the 
commutator  end  of  the  armature,  as  breaks  in  the  wire  are 
most  frequent  where  the  connections  are  made  with  the 
commutator  segments.  In  either  of  the  cases  we  have  been 
discussing  it  is  best  not  to  try  any  makeshifts,  but  to  cut  the 
machine  out  until  it  can  be  properly  repaired.  A  temporary 
remedy  sometimes  applied  in  such  a  case  is  to  cut  off  the 
defective  coil  from  the  commutator  bars  with  which  it  is 
joined,  and  then  temporarily  to  connect  the  disconnected 
bars  to  those  next  succeeding ;  but  it  is  not  advisable  to  do 
this  unless  driven  to  it. 

In  addition  to  the  causes  of  sparking  already  enumerated, 
there  is  a  tendency  for  sparks  to  flash  around  the  commutator 
over  several  segments.  This  is  most  often  observed  where 
carbon  brushes  are  used,  and  is  usually  a  result  of  carbon 
dust  getting  into  the  insulation  between  the  segments  and 
over  the  surface  of  the  commutator  generally.  It  is  often 
accompanied  by  heating  of  the  commutator,  and  never  occurs 
where  proper  care  is  taken. 

Heating  in  either  the  field-magnet  coil  or  the  armature  of 
a  dynamo  is  generally  due  to  one  of  two  causes — overloading 
or  short  circuits ;  overloading  can  be  told  by  the  condition  of 
the  ammeter,  and  most  often  results  in  railway  power  stations 
from  a  ground  on  the  line,  although  the  fuses  will  usually 
take  care  of  the  machines.  The  heating  due  to  short  circuits 
in  the  armature  we  have  already  mentioned.  In  addition 
there  may  be — particularly  when  the  machine  is  first  set 
up — moisture  in  the  armature  coils,  producing  a  general 
case  of  short  circuit  through  the  insulation.  Where  this 
is  present  the  armature  usually  feels  moist,  and  may  even 
steam.  It  is  a  rather  unusual  condition,  and  can  be  best 
remedied  by  drying  the  armature  very  gently  for  a  consider- 
able time. 

Passing  a  current  through  it  is  the  easiest  way  to  do  this, 


THE    STATION.  199 

although  the  amount  used  should  not  exceed  the  regular  cur- 
rent for  which  the  armature  is  intended. 

Heating  in  field-magnet  coils  may  arise  from  forcing  the 
voltage,  thus  sending  through  the  coils  a  greater  current 
than  that  for  which  they  were  designed ;  or  from  a  genuine 
short  circuit  in  the  coils,  not  a  usual  occurrence,  and  easily 
discovered  by  measuring  the  resistance  of  the  two  or  four 
•coils  with  which  the  machine  is  wound  and  comparing  them 
each  to  each.  If  the  difference  in  resistance  rises  to  more 
than  a  few  per  cent.,  there  is  probably  a  short  circuit. 
Moisture  may  get  into  the  field  coils  just  as  in  the  armature, 
and  is  expelled  in  the  same  way. 

Heating  of  the  commutator  may  be  due  to  general  overload, 
or  to  short  circuits  between  the  segments,  due  usually  to 
particles  of  metal  or  carbon  from  the  brushes.  The  first 
case  may  be  detected  by  the  ammeter,  the  second  by  the 
localized  heating  and  the  sparking  that  ensues.  Cleaning 
very  carefully  is  the  only  suitable  remedy. 

One  of  the  commonest  troubles  encountered  in  an  electric 
station  of  any  kind  is  the  heating  of  the  bearings  in  one  or 
more  of  the  dynamos ;  this  is  generally  due  either  to  lack  of 
oil  or  to  excessive  pressure  coming  from  an  overload.  With 
the  ordinary  types  of  railway  generators,  in  which  the  bear- 
ings are  self -oiling,  there  is  little  likelihood  of  the  first  cause 
producing  any  serious  results,  unless  the  oil  well  leaks  or  is 
extraordinarily  neglected ;  and  a  glance  at  it  will  tell  whether 
the  trouble  is  there  to  be  sought.  Occasionally  the  armature 
shaft  may  be  sprung,  or  the  bearings  may  be  out  of  line, 
although  neither  of  these  conditions  is  common.  In  the 
former  case,  the  armature  turns  hard  and  is  likely  to  stick  at 
a  particular  point;  in  the  latter,  the  shaft  still  turns  with 
difficulty,  but  with  nearly  equal  difficulty  all  the  way  round, 
and  the  revolution  becomes  much  easier  if  the  bearings  are 
slightly  loosened  from  their  foundations.  There  is  no  help 
for  a  sprung  shaft,  while  the  bearings,  if  out  of  place,  can 
be  aligned.  Neither  of  these  difficulties  is  as  common,  how- 
ever, as  a  hot  bearing,  due  either  to  the  pressure  of  the 
.shoulder  of  the  pulley  side  wise  against  the  bearing  or  too 
great  belt  tension. 


200  THE    ELECTRIC    RAILWAY. 

In  eithei  case  the  bearing  on  the  pulley  end  will  be  heated 
more  than  the  other.  If  the  trouble  is  due  to  lateral  thrust — 
as  can  be  easily  told  by  trying  to  push  the  armature  back  and 
forward  in  its  bearings  while  the  machine  is  running — the  belt 
pull  should  be  aligned.  Lateral  play  of  perhaps  an  inch  is 
allowed  on  almost  all  dynamos,  so  that  with  ordinary  care 
there  need  be  no  trouble  from  this  source. 

If  the  heating  is  simply  a  case  of  too  great  belt  tension, 
which  can  generally  be  told  by  inspection,  the  only  thing 
to  be  done  is  to  ease  the  belt ;  the  trouble  is  unlikely  to  occur 
at  all  if  the  bearings  are  looked  after  and  kept  in  proper  con- 
dition. The  greater  the  area  of  contact  on  the  pulley  can  be 
made,  either  by  using  a  larger  pulley  on  the  machine  or  a 
smaller  one  on  the  driving  shaft,  or 'by  using  wider  pulleys 
and  belting,  the  more  easily  the  same  power  can  be  trans- 
mitted, with  less  pressure. 

It  is  not  a  good  plan  to  try  to  cool  dynamo  bearings  with 
water,  for  water  is  not  a  pleasant  thing  to  have  in  the  vicinity 
of  an  armature ;  better  cut  out  the  machine  until  it  can  be 
fixed,  or,  if  it  be  absolutely  necessary  to  run,  the  very  careful 
application  of  ice  may  sometimes  relieve  the  difficulty. 

Occasionally  a  dynamo  will  positively  refuse  to  do  its  work ; 
and  perhaps  the  most  frequent  causes  are  a  flying  short  circuit 
in  the  armature,  such  as  has  just  been  mentioned,  or  a  break 
or  bad  connection  in  the  field  coils.  If  the  former  is  the 
case,  separate  excitation  by  one  of  the  other  machines  will 
soon  locate  the  trouble ;  if  the  latter,  measuring  the  resistance 
of  the  field  coils  will  generally  disclose  the  difficulty.  Some- 
times in  setting  up  the  machine  an  accidental  bad  connection 
may  pass  unnoticed  until  an  attempt  is  made  to  run.  If  a 
dynamo  has  been  assembled  recently,  there  may  be  a  bad 
magnetic  joint  between  the  yoke  and  the  magnet  cores, 
when  the  machine  will  fail  to  excite  properly.  This  will  be 
found  by  inspection,  and  it  is  remedied  without  difficulty  by 
doing  the  work  over  again  more  carefully. 

Setting  up  or  taking  down  a  dynamo  is  a  rather  difficult 
matter,  and  in  a  permanent  station  it  is  a  very  good  idea  to 
have  a  simple  traveling  crane  for  the  purpose  of  doing  such 
work  as  may  be  required.  Where  this  does  not  exist,  tempo- 


THE    STATION.  2OI 

rary  supports  can  be  erected  and  a  differential  tackle  will  do 
the  work.  If  the  traveling  crane  is  at  hand,  the  removal  of 
an  armature  becomes  a  simple  matter,  for  its  weight  can 
be  taken  by  the  tackle  and  it  can  then  be  slipped  out  of  posi- 
tion by  a  single  movement  of  the'  crane ;  the  yoke  or  other 
attachments  which  may  be  in  the  way  being  previously  re- 
moved. Such  a  course  is  only  necessary  in  very  large  arma- 
tures, for  small  ones  can  be  easily  handled  by  a  gang  of 
men,  the  shaft  always  being  so  blocked  up  as  not  to  bring 
the  armature  down  on  the  pole  pieces.  In  shifting  an  arma- 
ture with  the  crane  or  temporary  tackle  the  ropes  and  chains 
should  never  be  allowed  to  touch  the  windings;  the  grip 
should  be  entirely  on  the  shaft. 

MINOR   APPARATUS. 

As  regards  the  subsidiary  apparatus  required  to  run  a  sta- 
tion, every  switch,  cut-out  and  lightning  arrester  should  be 
kept  in  thoroughly  good  working  order,  with  no  bad  contacts, 
and  no  dirt  allowed  to  accumulate.  Lightning  arresters 
should  be  set  with  the  plates  or  points  across  which  the 
lightning  is  expected  to  jump  very  close  together,  from  a 
sixteenth  to  an  eighth  of  an  inch,  and  should  be  kept  free 
from  dust,  which  might  otherwise  cause  a  short  circuit.  Gen- 
erally only  those  forms  should  be  used  in  which  after  one 
lightning  discharge  the  arrester  is  automatically  reset  and 
ready  for  another. 

The  measuring  instruments  of  the  station  should  be  com- 
pared now  and  then  with  each  other  and  with  standard 
instruments,  and  the  engineer  or  superintendent  of  the  sta- 
tion ought  to  take  pains  to  understand  the  function  of  each 
piece  of  subsidiary  apparatus,  of  whatever  kind,  with  which 
he  has  to  do.  Specific  information  in  these  matters  can  best 
be  obtained  from  the  company  which  furnishes  the  particular 
forms  of  apparatus  employed,  as  there  are  frequently  minor, 
though  important,  details  peculiar  to  each  especial  make. 


CHAPTER   VII. 

THE   EFFICIENCY    OF   ELECTRIC    TRACTION. 

WHATEVER  may  be  the  advantages  of  electric  traction, 
whatever  its  convenience  as  a  means  of  rapid  transit,  it  is  on 
its  efficiency  that  its  ultimate  importance  must  depend.  We 
must  realize  at  the  start  that  the  electric  motor  is  not  a  prime 
mover,  a  fundamental  source  of  energy ;  it  only  furnishes  a 
very  perfect  and  elegant  means  of  utilizing  electrical  en- 
ergy, already  generated  by  some  prime  mover,  at  the  point 
where  it  may  be  most  convenient  to  employ  it,  whether  that 
point  be  fixed,  as  in  the  case  of  stationary  motors,  or  moving, 
as  in  the  case  of  street  railways.  Advantages  may  be  and  are 
gained  by  employing  motors,  sufficient  to  offset  considerable 
losses  in  the  necessary  transmission  and  transformation  of 
electrical  energy,  but  if  these  losses  rise  above  a  certain 
amount  the  system  must  inevitably  be  a  commercial  failure. 

Let  us  look,  then,  deliberately  at  the  series  of  transmissions 
and  transformations  necessary  in  electric  traction,  and  form 
as  close  estimates  as  possible  of  the  losses,  their  magnitudes, 
and  the  most  practicable  means  for  reducing  them  to  a  more 
satisfactory  figure.  The  first  transformation  of  energy  is 
from  the  pressure  of  steam  generated  in  the  boilers  to  the 
rotary  motion  produced  by  the  engine  and  employed  in  driv- 
ing the  dynamos. 

Then  the  mechanical  energy  obtained  is  first  transferred, 
through  the  medium  of  shafting  or  belting,  to  the  dynamo, 
where  it  is  again  transformed  and  appears  as  electrical  cur- 
rent on  the  line.  In  this  convenient  shape  it  is  transferred, 
with  little  loss,  to  the  point  on  the  line  where  the  motor  or 
motors  may  happen  to  be.  There  it  undergoes  another  trans- 
formation in  the  motor  back  to  mechanical  energy,  which 
is  then  transferred,  through  the  medium  of  gearing  of  one 
sort  or  another,  from  the  armature  shaft  to  the  car  wheels. 


THE   EFFICIENCY    OF    ELECTRIC    TRACTION.  2O3 

Fortunately,  the  losses  at  several  points  in  this  somewhat 
complicated  system  of  transmutations  are  comparatively 
small ;  and  for  practical  purposes  we  may  consider  the  losses 
to  be  substantially  as  follows :  first,  the  losses  in  the  engine 
and  attachments ;  second,  those  in  the  dynamo ;  third,  those 
on  the  line;  fourth,  those  in  the  motor,  fifth,  those  in  the 
gearing.  Luckily,  not  all  these  are  serious.  In  the  art  of 
electric  traction  as  to-day  practiced,  their  relative  magnitudes 
are  about  as  follows :  the  most  formidable  are  the  first  and 
the  last;  they  are  of  about  the  same  magnitude,  varying 
enough  in  different  cases  to  render  it  quite  impossible  to  say 
offhand  which  is  the  larger.  Then  come  the  losses  in  the 
dynamo  and  motor,  generally  smaller  than  either  of  the 
former,  and  that  in  the  motor  being  somewhat  the  larger. 
Finally,  the  loss  on  the  line,  which  in  many  cases  is  the  least 
of  all.  Reduction  of  gearing  has  in  some  cases  made  that 
source  of  loss  relatively  small,  but  too  often  at  the  expense 
of  motor  efficiency. 

Let  us  take  up  these  several  causes  of  inefficiency  in, 
order : 

ENGINE    EFFICIENCY. 

Of  the  total  indicated  horse-power  developed  by  ordinary 
engines  running  at  full  load,  nearly  10  per  cent,  is  consumed 
in  friction  of  the  moving  parts.  Occasionally  the  loss  may 
be  less  than  5  per  cent. ;  not  infrequently  it  rises  to  1 5 
per  cent.  Its  amount  is  nearly  a  constant,  not  a  constant  per 
cent.  It  may  increase  or  diminish  with  the  load,  but  gener- 
ally remains  somewhere  nearly  uniform. 

It  is  probable  that  every  engine  has  a  particular  load  for 
which  the  friction  is  a  minimum,  owing  to  the  fact  that  the 
strains  to  which  the  machine  is  subjected  produce  slight 
flexures  that  vary  the  resistance  at  the  bearing  surfaces ;  for 
the  purpose  in  hand  a  safe  estimate  for  the  friction  is  10  per 
cent,  of  the  rated  capacity  of  the  machine,  and  this,  by  the 
convention  usually  adopted  among  engine  builders,  is  its 
output  for  boiler  pressure  of  from  80  to  100  pounds  and  a 
cut-off  of  about  one-fourth  stroke.  A  few  concrete  cases 
may  be  of  interest  to  the  reader. 


204  THE    ELECTRIC    RAILWAY. 

TYPE   OF   ENGINE.  SPEED.  I.  H.  P.         FRICTION  IN  H.   P. 

Buckeye 280  23  5 

Westinghouse 3°°  °4 

Armington  &  Sims 290  •                   80  9 

Corliss 88  120  10 

Compound  condensing —  347  44 

These  are  merely  examples  to  show  the  general  magnitude 
of  the  friction.  The  differences  in  friction  between  two 
engines  of  the  same  make  and  the  same  engine  at  differ- 
ent times  are  as  great  or  greater  than  any  difference  that  is 
likely  to  exist  between  two  similar  types  of  engine  of  like 
size.  Relatively,  friction  is  less  in  large  engines. 

In  railway  power  stations  it  is  the  almost  invariable  rule, 
at  present,  that  the  driving  engines  are  used  not  at  their  full 
output,  but  at  something  considerably  below  it.  The  exceed- 
ingly irregular  demands  for  power  on  small  roads  make  the 
average  load  throughout  the  day  decidedly  less  than  the  full 
output  of  the  engine.  The  result  of  this  state  of  things  is 
that  the  friction,  not  a  serious  loss  when  working  at  full  load, 
becomes  an  important  cause  of  inefficiency.  Take,  for  ex- 
ample, an  engine  rated  at  100  horse-power,  driving  a  dynamo 
of  similar  capacity:  the  loss  by  friction  in  the  engine  will  be 
about  10  horse-power,  irrespective  of  load;  and  used  as  such 
engines  generally  would  be  on  roads  of  comparatively  small 
size,  the  average  load  seldom  would  be  more  than  one-half 
the  figure  above  named.  Consequently,  20  per  cent,  of  the 
indicated  horse-power  would  be  wasted  in  worse  than  useless 
friction.  If  the  average  load  should  fall  to  30  horse-power, 
a  condition  by  no  means  infrequent  on  small  roads,  about  30 
per  cent,  of  the  indicated  horse-power  is  lost,  and  so  on. 

In  two  cases  that  have  fallen  under  the  writers'  observation 
the  efficiencies  of  the  engines,  owing  to  underloading,  were 
reduced  to  70  and  68  per  cent.,  respectively;  while  even  at 
the  greatest  output  noted  during  the  day's  run  the  efficiencies 
were  only  85  and  84  per  cent.  On  another  road,  under  very 
different  .conditions,  the  efficiency  of  the  engine  at  mean  load 
was  88  per  cent. ;  at  maximum  load  for  the  day,  92  per  cent. 

The  differences  between  these  three  cases  are  exceedingly 
instructive.  In  the  first-mentioned  one  the  engine  was  a 
125-horse-power  Corliss,  driving  two  30,000- watt  dynamos 


THE    EFFICIENCY    OF    ELECTRIC    TRACTION.  20$ 

through  the  medium  of  a  counter-shaft.  The  mean  load  was 
about  40  horse-power  and  the  maximum  load  80  horse-power 
— six  cars  being  in  regular  service  on  the  line. 

In  the  second  case  two  Armington  &  Sims  engines  were 
employed,  belted  directly  to  two  6o,ooo-watt  generators  run- 
ning in  parallel.  Seven  cars  were  used  on  the  line.  The 
average  indicated  horse-power  was  51.4  and  the  maximum 
indicated  horse-power  108.  In  the  third  case  the  engine  in 
question  was  a  Ball  machine  of  1 50  rated  horse-power,  driving 
two  5o,ooo-watt  dynamos.  Fourteen  cars  were  in  regular  use. 
The  mean  indicated  horse-power  was  86.4  and  the  maximum 
horse-power  124.  The  first  two  cases  are  examples  of  how 
not  to  design  a  railroad  power  plant.  The  third  is  a  specimen 
of  fairly  good  engineering  practice,  although  the  dynamos 
might  have  been  somewhat  larger  to  good  advantage. 

The  more  nearly  the  average  load  on  the  engine  approxi- 
mates to  its  full  rated  capacity,  the  greater  the  efficiency  that 
can  be  secured.  A  properly  constructed  steam  engine  can  be 
worked  for  short  periods  considerably  above  its  nominal  horse- 
power without  injury ;  and  it  is  more  desirable  to  do  this 
than  to  allow  its  average  load  to  become  low. 

For  example,  the  engine  of  the  third  road  mentioned  was 
worked  occasionally  as  high  as  215  horse-power  for  a  few 
moments,  to  supply  a  sudden  and  unusual  demand  for  power 
on  the  line.  It  was  quite  capable  of  doing  this  without  dam- 
age, and  it  was  only  by  this  means  that  the  unusual  efficiency 
mentioned  could  have  been  secured.  To  work  an  engine, 
then,  most  efficiently,  so  far  as  loss  by  friction  is  concerned, 
it  is  necessary  to  keep  it  loaded  as  nearly  up  to  its  rated 
capacity  as  possible.  On  small  roads,  where  the  maximum 
electrical  output  may  be  three  or  four  times  the  average,  this 
can  only  be  done  by  occasionally  working  the  engine  up  to 
its  extreme  capacity — in  other  words,  by  employing  an  en- 
gine with  a  wide  range  of  cut-off,  so  that  the  steam  may 
follow  almost  up  to  full  stroke  if  necessary.  In  addition 
to  losses  by  friction  in  the  engine  there  are  also  losses  in 
shafting,  if  it  is  employed. 

It  almost  goes  without  saying  that  the  best  engine  efficiency 
will  be  obtained  by  belting  or  coupling  the  dynamos  directly 


206  THE   ELECTRIC    RAILWAY. 

to  the  engines;  and  for  this  purpose,  unless  the  machines  are 
very  large,  a  high-speed  engine  is  preferable,  since  it  not 
only  regulates  better  under  extreme  variations  of  load,  but 
usually  allows  a  wide  range  of  cut-off. 

And  this  brings  us  to  another  very  important  consideration 
in  efficiency.  We  have  already  seen  that  underloading  an 
engine  produces  a  needlessly  large  loss  in  friction  and  re- 
duces the  efficiency  of  the  system;  but  it  also  does  worse 

than  this it  lessens  the  efficiency  of  the  engine  directly  and 

considerably.  If  the  steam  be  permitted  to  expand  to  many 
times  its  original  volume  in  the  cylinder,  there  will  ensue 
an  amount  of  condensation  that  very  materially  increases  the 
amount  of  steam  necessary  to  produce  a  given  effort.  In 
other  words,  if  the  steam  is  cut  off  too  early  in  the  stroke  it 
is  employed  at  a  great  disadvantage,  and  the  amount  of  coal 
that  must  be  burned  under  the  boilers  to  furnish  the  required 
number  of  indicated  horse-power  in  the  engine  will  be  greatly 
increased.  On  the  other  hand,  if  the  cut-off  be  too  late,  as 
would  happen  if  an  engine  were  regularly  overloaded,  the 
steam  passes  into  the  exhaust  before  it  can  be  employed  to 
the  best  advantage ;  and  there  is  a  corresponding  increase  in 
the  amount  of  fuel  required. 

For  any  given  pressure  of  steam  there  is  a  particular  ratio 
of  expansion  that  will  use  the  steam  in  the  most  economical 
way,  and  consequently  will  require  the  minimum  amount  of 
coal  per  horse-power  hour.  A  considerable  amount  of  inves- 
tigation has  been  spent  in  finding  this  point ;  and  the  best 
formula  that  has  yet  been  produced  is  probably  the  following, 
due  to  Emery : 

i  i 

r   ~   I  -\-p_ 

22 

Where  r  is  the  ratio  of  expansion,  that  is,  the  ratio  of  the 
volume  of  steam  admitted  to  its  final  volume,  and  /  is 
the  absolute  pressure  in  pounds  per  square  inch,  that  is,  the 
pressure  of  the  steam  plus  the  atmospheric  pressure. 

For  the  boiler  pressures  generally  employed,  90  to  100 
pounds  to  the  square  inch,  the  most  economical  point  of  cut- 
off is  between  one-fourth  and  one-fifth  of  the  stroke.  This 


THE    EFFICIENCY    OF    ELECTRIC    TRACTION.  2O/ 

is  about  the  point  generally  taken  by  engine  builders  in 
designating  the  nominal  horse-power  of  their  engines,  as  has 
been  previously  explained.  There  is,  then,  a  double  reason 
for  working  an  engine  up  to  its  full  rated  horse-powder. 
First,  it  reduces  the  friction  to  as  insignificant  a  factor  as 
possible ;  and,  second,  it  employs  the  steam  to  the  best  advan- 
tage. As  a  mattet  of  fact,  overloading  is  less  injurious  in 
the  latter  respect  than  underloading;  so  that  we  have  an 
additional  reason  for  not  employing  engines  larger  than  are 
necessary  to  do  the  wrork  required. 

Compound  or  triple-expansion  engines,  in  which  the  total 
expansion  of  steam  is  carried  through  several  cylinders 
instead  of  being  confined  to  one,  do  not  suffer  as  severely 
from  variations  in  the  expansion  ratio  as  simple  engines ;  so 
that  they  are  not  only  more  economical  per  se,  but  are  better 
adapted  for  wrork  in  which  the  variations  of  load  are  likely  to 
be  large.  It  is  not  our  purpose  to  go  again  here  into  the  de- 
tails of  the  question  of  engine  economy,  but  it  may  be  stated 
that  compound  engines  require  for  a  given  output  about  two- 
thirds  as  much  coal  as  simple  engines,  and  triple-expansion 
condensing  engines  only  about  two-fifths  as  much- — the  ma- 
chine in  each  case  being  worked  at  its  full  normal  load. 

For  maximum  engine  efficiency  and  economy,  the  facts 
would,  then,  indicate  the  use  of  the  compound  or  triple- 
expansion  condensing  engine,  loaded  as  nearly  as  possible  to 
its  full  rated  capacity  under  ordinary  circumstances,  and 
allowed  now  and  then  to  work  up  to  nearly  its  extreme  power, 
in  case  of  .an  emergency.  If  simple  engines  are  used,  the 
same  requirements  as  to  load  follow.  Engineers  are  often 
called  upon  to  decide  between  the  use  of  a  high-speed  engine 
with  slide  or  piston  valves  and  the  low-speed  engine  with 
Corliss  or  equivalent  gear.  For  most  kinds  of  service  the 
latter  has  the  advantage  in  economy;  in  street-railway  work, 
however,  the  conditions — except  in  quite  large  stations — are 
reversed;  since,  in  the  first  place,  the  Corliss  engine  has  a 
smaller  range  of  cut-off  than  the  high-speed  types,  and  con- 
sequently cannot  be  regularly  worked  at  so  near  its  full 
power,  if  the  variations  in  load  are  to  be  large.  Secondly, 
w^hen  worked  considerably  below  its  capacity  it  suffers  more 


208 


THE    ELECTRIC    RAILWAY 


severely  from  cylinder  condensation,  on  account  of  the  large 
exposed  surfaces.  In  cases  where  the  maximum  load  does 
not  exceed  twice  the  average  load  the  Corliss  valve  gear  will 


FIG.  93.-AVERAGE   LOAD  CARD.      CORLISS  ENGINE. 


give  excellent  results."-  We  cannot  emphasize  this  question 
of  underloaded  engines  more  forcibly  than  by  showing  the 
annexed  indicator  cards,  taken  from  the  first  two  engines 
referred  to  at  the  beginning  of  this  chapter. 

Figs.  93  and  94  are  respectively  the  diagrams  for  mean  and 


FIG.  94.— MAXIMUM  LOAD  CARD.    CORLISS  ENGINE. 

maximum  loads  of  the  Corliss  engine  in  the  power  station  at 
Lafayette,  Ind.f    Figs.  95  and  96  are  the  same  for  one  of  the 


*  We  speak  of  Corliss  engines  in  this  treatise  as  embodying  the  important  principle  of 
independent  admission  and  exhaust  valves.  All  that  is  said  of  them  applies  with  equal 
force  to  some  other  engines  possessing  this  same  characteristic.  Some  of  these  have  a 
"positive"  valve  gear  (i.e.,  with  all  the  valves  opened  and  closed  by  the  engine  itself) 
and  can  be  run  at  a  higher  speed  than  the  regular  Corliss  type. 

t  'fhc  Electrical  World,  June  22,  i88g. 


THE    EFFICIENCY    OF   ELECTRIC   TRACTION.  209 

engines  in  the  Syracuse,  N.  Y.,  power  station,  tested  by  Mr. 
Hulett.*  A  glance  will  show  the  advantages  that  would  exist 
in  a  case  where  the  mean  load  is  at  an  economical  cut-off 
instead  of  a  somewhat  inefficient  one,  as  at  Syracuse,  or  the 
even  worse  state  of  things  at  Lafayette. 

Nevertheless,    the    card    given    by  the   Corliss   engine    is 
noticeably  better  in  configuration  than  the  other;  and  were 


FIG.  95.— AVERAGE  LOAD  CARD.    HIGH-SPEED  ENGINE. 

it  not  for  the  exceedingly  short  cut-off  and  consequent  heavy 
cylinder  condensation,  the  superiority  of  the  valve  gearing 
wrould  have  asserted  itself  in  a  diminished  amount  of  fuel. 
As  the  case  stood,  however,  the  Syracuse  engine  gave  the 
indicated  horse-power  hour  on  5.3  pounds  of  coal,  as  against 
7.3  in  the  other. 

To  sum  up,  then,  the  golden  rule  for  efficiency  in  power 
stations  is  to  use  the  engine  at  its  most  economical  point  of 
cut-off  when  delivering  its  average  output;  and  this  will  be 
in  nearly  every  case  at  the  full  nominal  capacity  of  the  en- 


FIG.  96.— MAXIMUM  LOAD  CARD.    HIGH-SPEED  ENGINE. 

gine.  Employ  compound  or  triple-expansion  condensing 
engines  wherever  the  cost  of  fuel  renders  it  desirable.  If 
simple  engines  are  used,  employ  heavily  built  high-speed 
engines  belted  directly  to  the  generators,  unless  the  conditions 
are  such  that  the  variations  in  load  are  not  much  more  than 
50  per  cent,  of  the  average,  when  an  engine  of  the  Corliss  or 
similar  type  equipped  with  a  heavy  fly-wheel  will  econo- 

*  The  Electrical  World,  August  16,  1890. 


2IO  THE    ELECTRIC    RAILWAY. 

mize  fuel:  With  a  thoroughly  well-designed  power  station, 
the  efficiency  of  the  engine,  so  far  as  frictional  losses  are 
concerned,  maybe  raised  to  between  85  and  95  per  cent., 
with  direct  belting  to  the  dynamos  or  good  counter-shafting; 
while  under  less  favorable  circumstances  it  is  likely  to  fail  as 
low  as  70  per  cent.* 

DYNAMO    EFFICIENCY. 

Much  that  has  been  said  regarding  the  evil  effects  of 
underloading  engines  applies  also  to  dynamos,  but  there  are 
important  differences  between  the  two  cases.  There  is  noth- 
ing in  the  dynamo  corresponding  to  the  inefficient  utilization 
of  fuel  that  we  find  in  an  underloaded  engine,  and  whereas 
the  losses  by  friction  in  an  engine  remain  nearly  constant, 
quite  irrespective  of  load,  in  the  dynamo  there  are  certain 
losses  that  decrease  very  rapidly  as  the  load  diminishes. 
Taking  the  dynamo  as  we  find  it,  it  may  be  worth  while  to 
glance  for  a  moment  at  the  various  causes  that  tend  to  dimin- 
ish its  efficiency. 

There  is,  of  course,  a  certain  amount  of  friction  in  the 
bearings,  and  besides  this  there  are  electrical  and  magnetic 
losses  due  to  the  reversals  of  magnetization  in  the  armature 
core  (hysteresis),  losses  by  eddy  currents  in  the  metallic  parts 
of  the  machine,  .energy  spent  in  keeping  up  the  magnet- 
ism of  the  field  magnets,  and,  finally,  a  very  considerable 
loss  due  to  heating  the  armature. 

The  true  frictional  loss  is  generally  rather  small  and  re- 
mains virtually  constant.  In  constant-potential  machines, 


*  It  may  be  well  here  to  note  the  practical  efficiency  of  the  steam  engine  as  a  mechanism 
for  transforming  the  heat  energy  of  coal  into  mechanical  power.  As  has  been  explained 
in  Chapter  II..  the  possible  efficiency  is  limited  by  the  practical  range  of  temperature 
attainable,  but  ivithin  this  limitation  the  best  engines  are  tolerably  efficient.  With 
compound  or  triple-expansion  condensing  engines  the  actual  efficiency  may  be  from  one- 
half  to  two-thirds  of  that  theoretically  possible  between  the  given  temperature  limits. 
With  most  engines  three  or  four  tenths  of  the  possible  efficiency  would  be  an  estimate 
more  nearly  in  accordance  with  fact.  To  take  a  concrete  case,  the  150  H.  P.  pumping 
engine  at  Pawtucket,  R.  I.  cards  from  which  are  shown  in  Figs.  23  and  24,  Chapter  II., 
during  a  careful  test  gave  the  following  results  •  Total  heat  received  by  the  engine  per 
hour,  2,427,198  units;  indicated  work,  143.49  H  P.— that  is,  368,769  heat  units;  actual 
efficiency,  15  per  cent.  Upper  limit  of  temperature,  356°  F.;  lower  limit,  100°  F.; 

— ~ — ?  =  .31.     Therefore  the   engine  in   question  gave    very   nearly  half   the   possible 

efficiency.    The  coal  consumed  was  1.54  pounds  per  indicated  H.  P.  hour,  the  steam  used 
13.64  pounds. 


THE    EFFICIENCY    OF    ELECTRIC    TRACTION.  211 

losses  from  hysteresis  and  eddy  currents  and  the  loss  in  the 
field  magnets  are  also  practically  constant ;  but  the  energy 
spent  in  heating  the  armature  increases  very  rapidly  as  the 
current  increases.  It  is,  in  fact,  equal  to  the  resistance  of 
the  armature  multiplied  by  the  square  of  the  current.  Thus, 
with  an  armature  resistance  of  one-tenth  of  an  ohm  and  a  cur- 
rent of  fifty  amperes  flowing,  the  loss  in  the  armature  will  be 
250  watts;  while  with  100  amperes  it  will  rise  to  1,000 
watts.  Consequently,  when  the  load  on  the  dynamo  is  di- 
minished, its  efficiency  does  not  fall  anywhere  nearly  so 
rapidly  as  the  efficiency  of  the  driving  engine  falls,  because, 
while  the  losses  in  the  latter  remain  constant,  those  in  the 
armature  are  much  diminished  by  the  lessened  heating  of 
the  armature. 

With  machines  having  a  comparatively  high  armature 
resistance  the  total  efficiency  may  fall  off  but  slightly  as  the 
current  diminishes.  We  frequently  hear  the  electrical  effi- 
ciency of  a  dynamo  mentioned,  but  the  phrase  is  apt  to  mislead ; 
for  in  practice  we  do  not  deal  with  the  electrical,  but  with 
the  commercial,  efficiency,  and  this  includes  not  only  losses 
in  the  armature  and  field  coils,  but  also  all  the  others  to  which 
we  have  alluded. 

With  the  best  forms  of  constant-potential  dynamo  now 
constructed,  the  commercial  efficiency,  that  is,  the  ratio  of  the 
power  supplied  at  the  pulley  to  the  electrical  energy  devel- 
oped on  the  line,  may  rise  slightly  above  90  per  cent.,  but 
more  often  falls  two  or  three  per  cent,  below  that  figure. 

Thus  a  dynamo  giving  60,000  watts  (about  80  horse-power) 
at  full  load  will  require  nearly  90  horse-power  to  be  sup- 
plied at  the  pulley  and  nearly  100  indicated  horse-power  at 
the  engine.  As  we  have  just  seen,  on  lighter  loads  the 
commercial  efficiency  of  the  dynamo  will  diminish,  though 
not  very  rapidly,  until  very  light  loads  are  reached  ;  in  other 
words,  until  the  loss  in  the  armature  becomes  quite  small  in 
comparison  with  the  losses  from  friction,  hysteresis,  and  eddy 
currents.  Fig.  97  shows  the  efficiency  curves  of  several  types 
of  machine  at  various  loads.  The  horizontal  scale  shows  the 
proportionate  load  on  the  machines,  the  vertical  scale  the 
efficiency  obtained  at  those  loads.  The  curve  numbered  I  is 


212 


THE   ELECTRIC    RAILWAY. 


for  an  English  incandescent  machine  with  magnets  of  the 
inverted  horseshoe  type,  intended  for  an  output  of  45,000 
watts.  Curve  II  is  from  a  Wenstrom  incandescent  dynamo 
of  about  the  same  size,  and  Curve  III  is  from  a  Thomson- 
Houston  railway  generator  of  60,000  watts  capacity.  It  will 
be  seen  that  from  half  load  to  full  load  the  efficiency  varies 
but  little,  while  below  half  load  it  falls  off  quite  rapidly.  It 
is  very  apparent,  then,  that  to  secure  the  best  efficiency  in  a 


PER  CENT  OF  FULL  LOAD 
FIG.  97.— CURVES  OF  DYNAMO  EFFICIENCY  AT  VARYING  LOAD. 

railway  power  station  it  is  necessary  to  operate  the  dynamos 
at  somewhere  nearly  their  full  output,  in  which  case  the 
capacity  of  the  machine  should  nearly  correspond  to  the 
maximum  continued  output  required. 

If  the  variations  in  load  are  likely  to  be  great  it  may  be- 
come necessary  to  work  the  dynamos  above  their  intended 
capacity,  for  a  few  minutes  at  a  time,  as  occasion  demands ; 
but  while-  this  overloading  is  quite  unnecessary  on  large 


THE    EFFICIENCY   OF   ELECTRIC   TRACTION.  213 

roads,  it  is  not  to  be  recommended  even  on  small  ones, 
unless  in  cases  where  the  overload  is  not  likely  to  continue 
for  more  than  a  few  moments.  A  safe  rule  is  to  provide  a 
dynamo  of  a  rated  capacity  equal  to  about  half  the  aggregate 
rated  capacity  of  the  motors.  This  will  be  ample,  unless  in 
the  case  of  very  small  roads  with  heavy  grades.  The  average 
applied  power  required  is  not  far  from  6  to  8  horse-power 
for  each  1 6-foot  car,  supposing  the  latter  to  be  equipped,  as 
usual,  with  two  15 -horse-power  motors;  it  is  unlikely  to  rise 
above  10  horse-power.  This  subject,  however,  has  been 
already  fully  treated  in  the  chapter  on  station  design. 

With  a  dynamo  equipment  thus  designed  the  average  out- 
put would  be  generally  a  little  over  one-half  the  full  capacity 
of  the  machines;  and  their  efficiency  should  consequently  be 
high,  something  like  85  or  90  per  cent.  Under  very  favor- 
able circumstances,  when  the  number  of  cars  in  operation  is 
so  large  that  the  maximum  current  required  at  any  time  upon 
the  line  does  not  greatly  exceed  the  average  current,  this 
efficiency  may  be  somewhat  increased;  though  it  cannot  be 
expected  to  reach,  or  to  rise  above,  90  per  cent.,  except  in 
rare  instances.  Taking,  now,  these  figures  with  regard  to 
dynamo  efficiency  in  connection  with  what  we  have  previously 
stated  about  engines,  we  may  be  able  to  form  a  fairly  accurate 
estimate  of  the  probable  station  efficiency — that  is,  the  ratio 
between  the  indicated  horse-power  at  the  engine  and  the 
electrical  horse-power  available  upon  the  line. 

There  is  certainly  room  for  considerable  improvement  in 
the  usual  practice,  particularly  in  the  earlier  stations.  The 
power  station  of  the  Lafayette,  Ind.,  street  railway,  tested 
by  one  of  the  authors,  gave  a  station  efficiency  of  but  40  per 
cent.,  owing  to  the  fact  that  the  engine  was  worked  at  less 
than  a  third  its  full  output  and  the  dynamos  at  less  than  a 
fifth.  The  power  station  at  Syracuse,  N.  Y.,  tested  by  Mr. 
Hulett,*  is  an  example  of  decidedly  better  practice.  Its  en- 
gines are  belted  directly  to  the  generators,  and  were  run  on 
an  average  at  about  a  third  of  their  full  output ;  the  dynamos, 
however,  of  twice  the  capacity  of  those  used  at  Lafayette, 
were  under  considerably  more  than  twice  the  average  load ; 

*  Tlie  Electrical  World,  August  16,  1890. 


214 


THE    ELECTRIC    RAILWAY. 


.and  consequently,  since  at  these  small  outputs  the  dynamo 
•efficiency  varies  rapidly  with  the  load,  the  Syracuse  dynamos 
must  have  given  altogether  better  commercial  efficiency.  In 
addition,  by  avoiding  the  use  of  a  counter-shaft,  the  power 
wasted  in  friction  was  relatively  less  than  in  the  case  first 
mentioned ;  so  that  the  total  average  efficiency  of  the  station 
rose  to  62.8  per  cent. 

Another  road,  instanced  by  Mr.  G.  W.  Mansfield,*  gave 


PER  CENT  OF   FULL  LOAD 

FIG.  98. -CURVES  OF  PLANT  EFFICIENCY  AT  VARYING  LOAD. 

an  average  station  efficiency  of  54.6  per  cent.  The  number 
complete  power-station  tests  published  is  comparatively 
small,  and  the  number  of  accurate  ones  smaller  still.  The 
three  above  mentioned  bear  internal  evidence  of  approximate 
accuracy,  which  is  more  than  can  be  said  of  some  others  that 
have  been  reported. 

With  oui^presen^ dynamos  and  engines,  a  station  efficiency 

+  The  Electrical  World.  August  ,7,  1889. 


THE    EFFICIENCY    OF    ELECTRIC    TRACTION.  21$ 

of  75  per  cent,  is  about  the  best  that  can  be  hoped  for  on 
ordinary  roads ;  and  this  can  only  be  obtained  by  the  greatest 
care  in  designing  the  station.  This  statement  is  amply  illus- 
trated by  Fig.  98,  which  shows  the  commercial  efficiency  of 
the  combined  engine  and  dynamo  plant  in  three  cases. 

The  first  curve,  i ,  represents  the  efficiency,  at  various 
loads,  of  a  Goolden  incandescent  dynamo  coupled  direct  to 
a  Willans  engine ;  the  dynamo  alone  had  a  commercial  effi- 
ciency at  full  load  of  91.2  per  cent.,  and  the  engine  showed 
about  the  amount  of  friction  usual  in  machines  of  its  size. 
It  will  be  seen  that  the  highest  commercial  efficiency  reached 
was  8 1  per  cent.,  while  at  half  load  it  fell  to  72.2  per  cent. 
Curve  2  shows  the  commercial  efficiency  of  an  Armington  & 
Sims  engine  coupled  directly  to  an  Edison  dynamo ;  the  half- 
load  efficiency  is  seen  to  be  about  70  per  cent.,  and  the  maxi- 
mum load  efficiency  was  71.4  per  cent.  Curve  3  shows  the 
efficiency  of  the  Lafayette,  Ind.,  power  station — a  Corliss 
engine  driving  three  Edison  dynamos  from  a  counter-shaft, 
two  of  them  railway  dynamos  of  30,000  watts  capacity  each, 
and  the  other  a  smaller  power  dynamo.  The  maximum 
commercial  efficiency  of  the  combination  was  65  per  cent., 
and  the  half-load  efficiency  less  than  60  per  cent. 

This  third  case  very  plainly  shows  the  effect  of  the  counter- 
shaft, and  the  use  of  two  railway  dynamos  instead  of  one  of 
double  the  capacity. 

The  obvious  moral  is  to  belt  or  couple  the  dynamos  directly 
to  the  engine,  whenever  possible.  Cases  often  arise  where  it 
becomes  desirable  to  drive  more  than  two  dynamos  from  a 
single  large  engine,  but  the  advantage  of  convenience  thus 
secured  is  obtained  at  the  expense  of  a  certain  small  amount 
of  efficiency.* 

Passing  now  from  the  consideration  of  the  power  station 
where  the  electrical  energy  is  generated,  let  us  take  up  the 
problem  of  its  efficient  transmission  to  the  point  where  it  is 
needed. 

*  Recent  developments  of  the  steam  turbine  may  affect  engineering  practice  consider- 
ably. A  late  test  of  a  loo-kilowatt  combined  turbine  and  dynamo  gave  at  full  load  the 
electrical  horse-power  hour  for  27.6  pounds  of  steam,  and  at  half  load  for  29  pounds  This 
is  a  better  result  than  has  ever  been  obtained  from  any  except  compound  engines,  and 
renders  possible  the  economical  use  of  direct-coupled  dynamo  and  engine  plants  of  a 
much  smaller  size  and  lower  first  cost  than  have  been  generally  contemplated. 


2i6  THE    ELECTRIC    RAILWAY. 

The  losses  encountered  in  transmitting  electrical  energy 
over  a  system  of  conductors  are  two  in  number.  First  in 
-importance  is  the  loss  due  to  the  resistance  of  the  line.  This 
is  equal,  in  watts,  to  the  resistance  multiplied  by  the  square  of 
the  current,  and  can  readily  be  determined  and  allowed  for. 
Second,  and  of  but  very  little  importance  under  ordinary 
circumstances,  is  the  loss  due  to  leakage — usually,  but  not 
always,  imperceptible.  In  overhead  systems  of  distribution 
as  now  constructed  the  insulation  resistance,  by  actual  meas- 
urement, can  be  readily  brought  to  over  a  megohm  per  mile 
of  line.  Therefore,  even  on  very  extensive  systems,  the 
insulation  will  be  amply  high  to  prevent  any  appreciable  loss 
of  power.  It  should  be  noted  that  doubling  the  length  of  a 
line  halves  the  insulation  resistance,  so  that  a  line  of  the 
insulation  above  mentioned  and  ten  miles  long  would  have 
a  total  insulation  resistance  of  100,000  ohms. 

EFFICIENCY    OF   THE    LINE. 

The  loss  due  to  line  resistance  may  evidently  be  made  as 
small  as  may  be  desired  by  increasing  the  cross-section  of 
the  conductors.  Of  course  it  is  not  economical  to  do  this 
beyond  a  certain  point,  for  the  cost  of  copper  would  then 
more  than  offset  the  cost  of  the  small  extra  amount  of  power 
demanded  by  a  line  of  higher  resistance.  At  great  distances 
from  the  power  station  the  line  is  comparatively  inefficient; 
near  the  power  station  there  is  almost  no  loss,  and  as  lines 
are  constructed  to-day  the  average  line  efficiency  is  generally 
from  90  to  95  per  cent.  For  example,  on  the  Lafayette 
street  railway  previously  mentioned  the  average  loss  on  the 
line  is  about  7  per  cent.,  on  the  Syracuse  railway  about  9 
per  cent.,  and  in  other  cases  even  smaller.  Where  the  sys- 
tem is  a  compact  one  with  plenty  of  feeders,  5  per  cent,  will 
readily  cover  the  losses  in  the  line.  If  a  wide  district  is 
reached  from  a  single  power  station,  twice  this  figure  is  a 
fair  allowance.  In  certain  cases  even  greater  loss  may  prove 
economical  in  the  long  run  ;  as  by  locating  the  power  station 
at  a  point  where  coal  is  cheap  and  water  for  condensation  is 
available,  the  operating  expenses  may  be  lessened  in  spite 
of  the  slightly  increased  output.  The  details  of  this  matter 


THE   EFFICIENCY    OF    ELECTRIC    TRACTION.  21^ 

are,  however,  not  suitable  for  treatment  here,  as  they  have 
been  discussed  at  length  in  the  chapter  on  the  line. 

Taking  into  account,  then,  the  losses  that  occur  in  the 
transmission  of  the  electrical  energy  from  the  point  of  gen- 
eration to  the  motors  on  the  cars,  and  combining  with  it  the 
station  efficiency,  we  find  that  in  the  most  favorable  case  a 
trifle  over  70  per  cent,  of  the  indicated  horse-power  at  the 
engine  may  be  applied  to  the  motors.  In  the  roads  now 
operated  the  proportion  is  much  more  likely  to  be  between 
55  and  60  per  cent. 

It  is  instructive  .thus  to  summarize  the  losses  as  each  suc- 
cessive step  in  utilizing  the  power  of  the  engines  at  the  cars 
is  passed,  for  it  helps  one  to  recognize  the  real  difficulties 
that  have  been  met  in  electric  traction  and  the  success  that 
has  been  obtained  in  spite  of  them.  On  the  whole,  the  result 
up  to  this  stage  of  the  operations  is  fairly  satisfactory.  The 
figures  thus  far  deduced  apply  with  equal  force  to  any  case 
of  electric  traction,  except  where  storage  batteries  are  em- 
ployed— a  method  which  will  be  treated  by  itself  in  a  follow- 
ing chapter. 

Where  distribution  is  by  means  of  underground  conduits 
instead  of  aerial  lines,  the  conditions  are  generally  the  same 
that  we  have  been  discussing.  The  losses  by  leakage  are 
likely  to  be  considerably  greater,  but  this  can  in  part  be  com- 
pensated by  a  slight  increase  in  the  cross-section  of  the  con- 
ductors. The  difficulty  thus  far  with  conduit  systems  has 
been  not  leakage  properly  so  called,  but  a  condition  of  things 
that  has  frequently  approximated  a  short  circuit.  With 
improved  conduit  construction  this  may  be  remedied.  Ex- 
perience has  shown  thus  far  that  the  danger  here  is  not  so 
much  low  general  insulation  as  complete  breaking  down  of 
the  insulation  at  one  or  many  points.  When  it  becomes  pos- 
sible to  save  conductors  from  actual  short  circuit,  it  will 
probably  also  be  possible  to  avert  any  disastrous  amount  of 
leakage.  Third-rail  and  similar  systems  of  supply  are  often, 
though  to  a  less  extent,  open  to  the  same  objections  that  apply 
to  the  conduit ;  but  if  the  insulation  can  be  kept  up  at  all,  it 
can  probably  be  brought  to  a  point  where  the  losses  in  the  line 
will  not  greatly  exceed  those  now  found  in  overhead  systems. 


2Ig  THE   ELECTRIC    RAILWAY. 

The  next  subject  for  consideration  is  the  efficiency  of  the 
electric  motor  as  a  converter  of  electrical  into  mechanical 
energy. 

EFFICIENCY    OF    MOTORS. 

So  far  as  losses  in  the  machine  proper  are  concerned,  the 
railway  motor  in  most  of  its  forms  gives  a  very  satisfactory 
efficiency.  Other  things  being  equal,  a  given  dynamo  elec- 
tric machine  is  somewhat  more  efficient  as  a  motor  than  when 
used  as  a  generator,  provided  the  conditions  are  nearly  the 
same.  One  reason  for  this  is  that  in  the  motor  whatever 
magnetizing  power  the  armature  coils  possess  is  added  to  the 
effective  magnetization  of  the  machine,  while  in  the  gener- 
ator it  is  subtracted  from  it.  For  this  reason  motors  are  fre- 
quently given  an  armature  relatively  more  powerful  than 
would  be  adopted  in  a  generator,  particularly  if  it  is  desirable 
to  construct  a  motor  of  high  output  compared  with  the  weight. 
As  an  example  of  the  effect  of  armature  reaction  in  helping 
the  efficiency  of  a  motor,  we  may  give  the  following  cases 
derived  from  the  experiments  of  Hopkinson.  Two  large 
dynamos  precisely  similar  in  construction  and  dimensions 
were  used  together,  one  as  a  generator  driving  the  other  as 
a  motor.  The  efficiency  of  the  first  machine  was  87.1  per 
cent,  as  a  generator  and  92  per  cent,  as  a  motor.  The  sec- 
ond machine  had  an  efficiency  of  84  per  cent,  as  a  generator 
and  89  per  cent,  as  a  motor. 

Street-railway  motors  as  now  generally  built  are  series- 
wound  machines ;  but  for  the  necessity  of  using  a  high  e1  actro- 
motive  force  and  reducing  the  weight  of  the  machine  to  the 
smallest  practicable  figures,  they  could  be  made  exceedingly 
efficient;  as  it  is,  there  is  little  to  complain  of  in  this  respect, 
although  the  losses  from  the  resistance  of  the  field  coils  and 
from  hysteresis,  in  rather  large  armatures,  are  generally 
more  considerable  than  they  would  be  in  dynamos  of  a  simi- 
lar output. 

The  principal  sources  of  loss  in  our  present  street-railway 
motors  are  the  regulating  devices  and  the  gearing.  In  start- 
ing a  soo-volt  motor  under  heavy  load,  it  is  necessary  in 
some  way  to  interpose  resistance  to  prevent  a  flow  of  current 


THE    EFFICIENCY   OF    ELECTRIC    TRACTION.  219 

so  great  as  to  endanger  the  armature.  It  would  evidently 
be  bad  practice  to  have  a  normal  field  resistance  high  enough 
to  accomplish  this  end,  for  after  the  motor  has  gathered 
headway  this  resistance  becomes  quite  unnecessary  and  is 
distinctly  harmful.  So,  in  the  motor  systems  most  generally 
employed,  special  regulating  coils  are  thrown  into  series  with 
the  motor  at  the  moment  of  starting,  and  then  more  or  less 
gradually  cut  out,  so  that  by  the  time  the  armature  has 
reached  its  full  speed  the  resistance  of  the  field  coils  is  little 
more  than  that  necessary  to  secure  the  requisite  magnet- 
izing force.  In  the  old  Sprague  motors  each  limb  of  the  field 
magnet  was  wound  with  three  separate  coils,  the  aggregate 
resistance  of  which  was  sufficient  to  serve  the  purpose  men- 
tioned. After  starting,  the  coils  at  the  first  in  series  were 
thrown  into  various  combinations,  and  were  all  finally  par- 
allel with  each  other;  so  that  the  final  resistance  was  thus  re- 
duced to  a  reasonable  amount. 

In  the  old  type  7  ^-horse-power  motors  the  initial  resist- 
ance, with  the  field  coils  all  in  series,  was  20  ohms  for  each 
motor,  the  final  resistance  3^  ohms.  The  later  type,  of  15 
horse-power,  was  wound  with  much  heavier  wire,  with 
greater  precautions  against  heating;  and  the  resistance 
varied  from  8.6  at  the  start  to  about  1.6  ohms  when  all  the 
coils  were  in  parallel. 

Later,  since  the  Sprague  system  has  passed  into  the  con- 
trol of  the  Edison  Company,  a  starting  coil  of  about  6  ohms 
resistance  has  been  placed  in  series  with  the  motors,  but  is 
immediately  cut  out  after  starting,  and  the  combinations 
then  proceed  as  before,  although  the  relative  resistances 
have  been  slightly  changed.  The  Thomson-Houston  motor 
system,  pursuing  substantially  the  same  course,  employs  a 
rheostat,  the  resistance  of  which  can  be  varied  within  quite 
wide  limits,  and  also  two  coils  on  each  limb  of  the  machine, 
which  are  first  used  in  series,  but  finally  one  of  them  is  cut 
out,  leaving  a  single  coil  of  low  resistance  in  circuit. 

The  YVestinghouse  device  for  regulation  is  like  the  Thom- 
son-Houston, except  that  the  rheostat  is  made  in  a  few  sec- 
tions instead  of  a  large  number. 

The  uncertainty  regarding  the  real  efficiency  of  street-rail- 


220  THE    ELECTRIC    RAILWAY. 

way  motors  as  they  are  now  used  in  practice  comes  from 
the  varying  resistance  of  the  regulating  devices,  and  only  a 
rough  estimate  can  therefore  be  formed  of  the  average  losses 
that  occur  from  heating.  In  most  forms  of  motor  the  hyster- 
esis losses  are  quite  heavy,  being,  at  the  average  speeds,  not 
far  from  200  watts  for  each  motor.  Some  careful  dynamom- 
eter tests  made  by  one  of  the  authors*  upon  Sprague  motors 
of  the  later  type  give  an  average  commercial  efficiency  for  a 
single  motor  of  83.6  per  cent. ;  with  two  motors  the  hysteresis 
losses  are  doubled,  the  power  is  generally  not  increased  in  the 
same  ratio,  and  the  final  result  for  the  average  efficiency  of 
the  pair  was  77.6  per  cent. ;  this  does  not  include,  however, 
the  losses  in  gearing.  The  figures  for  all  the  various  sys- 
tems are  not  easily  attainable,  but  it  is  safe  to  say  that  75  per 
cent,  would  be  a  fair  average,  taking  into  account  the  fact 
that  some  of  the  systems  use  one  motor  and  some  two,  and 
that  the  electrical  efficiencies  and  various  sources  of  loss  vary 
considerably,  according  to  the  type  of  motor  used. 

The  figures  thus  given  bring  us  at  once  face  to  face  with 

the  question  of  employing  a  single  large  motor  in  the  place 

of  the  two  generally  used.      That  the  efficiency  would  be 

raised  by  such  a  substitution  is  well-nigh  self-evident,  and  is 

amply  borne  out  by  experience.      The   causes  of  this  are, 

\  first,  the  advantage  in  efficiency  of  a  single  large  machine 

\  over  two  small  ones ;  the  electrical  efficiency  may  be  made 

I  somewhat  higher,   owing  to  the  advantage  of  substituting 

one  magnetic  circuit  for  two ;  and  the  losses  from  hysteresis 

/  and  friction  are  perceptibly  lessened. 

As  the  practical  aspect  of  this  problem  is  inextricably  in- 
volved with  the  efficiency  of  the  gearing,  the  latter  will  be 
discussed  before  proceeding  to  further  consideration  of  the 
question  in  hand.  With  regard  to  the  possible  average  effi- 
ciency of  street  car  motors,  it  is  quite  within  bounds  to  say 
that  with  a  properly  designed  single  motor  80  per  cent,  is 
quite  attainable ;  and  even  this  efficiency  may  be  somewhat 
raised,  though  it  is  hardly  likely  to  reach  90  per  cent.,  on 
account  of  the  present  necessity  for  regulating  devices  of 
some  kind  or  other  and  the  need  for  a  comparatively  light 

*The  Electrical  World,  May  31,  1890. 


THE    EFFICIENCY   OF   ELECTRIC    TRACTION.  221 

weight  machine.  In  most  street  car  systems,  even  to-day, 
the  armature  speed  is  somewhere  nearly  i.ooo  revolutions 
per  minute,  at  usual  car  speeds;  and  consequently  there 
must  be  a  reduction,  by  gearing,  to  one-tenth  or  one-twelfth 
the  armature  speed,  between  the  armature  and  the  car  axle. 
This  has  been  until  recently  generally  accomplished  by  a 
double  set  of  spur  gears.  The  efficiency  of  such  gearing  is 
usually  given  in  books  on  engineering  at  over  90  per  cent. 
for  each  set  of  gears,  and  with  reasonable  precautions  against 
Cirt  this  figure  may  be  reached  readily  enough. 

Boxed-in  gearing  is  obviously  more  advantageous  in  this 
respect  than  open  gears  exposed  to  the  weather.  In  the  test 
of  Sprague  cars  just  mentioned,  the  efficiency  of  the  gearing 
belonging  to  a  single  motor  was  found  to  be  a  trifle  over  85 
per  cent.  Even  the  best  spur  gearing,  protected  from  dirt, 
is  not  likely  to  give  90  per  cent,  for  the  double  reduction 
required.  The  joint  efficiency  of  the  gearing  of  both  motors, 
in  the  same  series  of  experiments  was  found  to  be  about  72 
per  cent. ;  showing  both  that  the  two  sets  of  gears  do  not  run 
in  perfect  harmony,  and  the  effect  of  doubling  the  fixed  losses. 

It  is  very  doubtful  if  a  pair  of  motors  can  ever  be  made  to 
run  perfectly  together;  for  even  if  the  two  machines  were 
originally  designed  to  be  as  nearly  alike  as  practicable,  there 
will  probably  be  slight  differences  between  their  respective 
speeds,  sufficient  to  throw  them  out  of  harmony  with  each 
other  and  increase  both  the  losses  in  the  motor  and  those  in 
the  gearing ;  and  this  is  more  emphatically  true  if,  as  gener- 
ally happens,  the  motors  are  now  and  then  taken  apart  for 
repairs  and  the  magnetic  circuit  thereby  impaired.  Lack  of 
general  cleanliness  about  the  motors,  and  penetration  of  oil  in- 
to the  joints  of  the  magnetic  circuit,  have  a  distinctly  deleteri- 
ous effect,  and  of  themselves  are  sufficient  to  produce  injurious 
differences  between  the  two  motors.  It  is  not  probable  that  a 
pair  of  motors  can  ever  be  brought  to  work  in  harmony 
for  any  great  length  of  time;  and  there  is,  therefore,  a  con- 
stant strain  upon  the  gearing  that  makes  itself  evident  ex- 
perimentally, as  has  just  been  indicated. 

During  the  last  six  months  all  the  prominent  manufact- 
urers of  electric  street  railway  motors  have  brought  out  low- 


222  THE    ELECTRIC    RAILWAY. 

speed  machines  with  but  a  single  speed  reduction  between 
the  armature  and  the  axle.  This  result  is  reached  either 
by  unusual  arrangements  of  the  magnetic  circuit,  or,  more 
often,  by  multipolar  motors.  The  armatures  of  these  ma- 
chines have,  generally  speaking,  a  speed  of  between  350  and 
450  revolutions  per  minute,  at  ordinary  car  speeds.  The 
motors  themselves  are  of  about  the  same  weight  as  the  older 
double-reduction  motors,  have  a  gear  efficiency  much  higher 

reaching  probably  fully  90  per  cent,  in  most  cases — and  the 

only  uncertain  factor  is  the  electrical  efficiency.  The  best  in- 
formation now  obtainable  indicates  that  it  is  hardly  as  high  as 
in  the  higher  speed  machines,  although  experience  in  design- 
ing has  taught  makers  to  obtain  a  better  average  efficiency  at 
varying  loads.  These  single-reduction  gear  motors  unques- 
tionably may  gain  enough  in  the  abolition  of  one  set  of  gear- 
ing to  more  than  compensate  for  the  loss  in  electrical  effi- 
ciency resulting  from  low  armature  speed.  This  gain  in  total 
commercial  efficiency  is  probably  trifling,  seldom  over  5  per 
cent.,  but  the  reduction  of  noise  and  of  wear  and  tear  on  the 
gearing  makes  this  type  of  motor  a  favorite.* 

Methods  of  reducing  the  axle  speed  other  than  spur  gearing 
are  not  now  generally  employed.  In  this  connection  should 
also  be  mentioned  the  use  of  connecting-rods  driving  di- 
rectly both  sets  of  wheels  from  a  single  very  low-speed 
motor,  a  case  which  has  already  been  discussed  in  Chapter 
III.  Belts  and  sprocket  chains  are  now  and  then  used,  but 
have  been  for  the  most  part  abandoned  by  reason  of  their 
uncertainty.  Worm  gearing  is  employed  in  a  few  cases — 
principally  storage  systems — and  has  probably  about  the 
same  efficiency  as  the  double-spur  gearing  which  has  already 
been  discussed. 


*  Some  recent  careful  tests  indicate  that  there  has  been  in  some  cases  too  great  a  sac- 
rifice of  electrical  efficiency  in  obtaining  low- armature  speed.  In  a  trial  of  three  types  of 
single  reduction  gear  motors,  the  speed  and  power  required  for  a  round  trip  over  a  long  and 
nearly  level  track  being  accurately  determined  in  each  case,  the  co-efficient  of  traction 
being  assumed  at  25  pounds  per  ton,  an  unusually  high  figure,  the  commercial  efficiencies 
were  as  follows:  Motor  I.,  37  per  cent.;  motor  II.,  58  per  cent.;  motor  III.,  75  per  cent. 
Motor  I.  was  undoubtedly  underloaded,  but  the  figures  disclose  no  material  gain,  to  say 
the  least,  over  the  older  types  of  motor. 


THE    EFFICIENCY    OF   ELECTRIC   TRACTION. 


223 


GENERAL   EFFICIENCY   WITH    ONE   AND   WITH   TWO    MOTORS. 

The  experiments  of  Hale*  indicate  an  even  greater  discrep- 
ancy between  the  efficiency  of  a  single  motor  and  of  a  pair 
than  the  experiments  already  mentioned.  Fig.  99  shows  the 
losses  from  the  various  parts  of  an  electric  street  railway 
system  as  given  by  Hale.  The  diagram  explains  itself  in 
part;  it  is  only  necessary,  in  addition,  to  state  that  the  differ- 


MILES  PER  HOUR 


ElK.  HorW,A'.  F. 


FIG.  99.— PROPERTIES  OF  MOTORS  AND  GEARING. 

ence  between  the  curves  G  and  E  represents  the  loss  in 
engine  and  dynamo  friction ;  that  between  E  and  D,  the 
electrical  loss  in  the  dynamo;  that  between  D  and  C,  the 
loss  in  the  line :  that  between  C  and  B,  the  electrical  loss  in 
the  motors;  and,  finally,  that  between  B  and  A,  the  loss  in 
friction  of  motors  and  gearing.  The  figures  must  be  taken 


The  Electrical  World,  May  17,  1890. 


•-4 


THE    ELECTRIC    RAILWAY. 


as  merely  approximate;  but  they  are  certainly  instructive, 
and  are  sufficiently  near  the  truth  to  emphasize  the  facts 
already  mentioned. 

From  what  has  already  been  said,  however,  it  is  clear  that 
quite  different  results  might  be  expected  according  to  the 
particular  form  of  motors  investigated.  The  total  efficiency 
of  the  combined  motor  and  gearing,  as  found  by  one  of  the 
authors,  was  for  one  motor  71.2,  and  for  the  pair  55.9 
per  cent.  This  is  about  a  fair  average.  It  is  very  certain, 
at  all  events,  that  a  single  motor  with  its  gearing  has  a  com- 
mercial efficiency  more  than  10  per  cent,  greater  than  in  the 
case  where  two  motors  are  employed. 

This  amount  is  certainly  worth  saving,  and  there  is  no 
reason  why  such  a  loss  should  be  incurred.  In  the  early 
days  of  electric  traction,  when  the  conditions  of  work  were 
not  sc  thoroughly  understood  as  now,  two  motors  were  sup- 
posed to  be  necessary ;  first,  for  security  in  case  of  accident 
to  one;  second,  for  better  driving  where  heavy  grades  were 
to  be  mounted.  As  regards  the  former  question  we  are  of 
opinion  that  with  the  latest  apparatus  these  precautions  are 
unnecessary,  as  greater  care  in  construction,  and  precautions 
against  injury  to  motors,  have  in  a  large  measure  obviated 
the  dangers  that  were  at  first  feared;  as  regards  the  second 
count,  it  is  altogether  probable  that  any  grade  which  should 
be  attempted  by  electric  street  cars  is  practicable  with  a 
single  motor  connected  to  both  axles.  It  should  be  stated, 
however,  that  there  is  one  case  in  which  the  employment  of 
two  motors  instead  of  one  possesses  such  considerable  advan- 
tages as  to  point  distinctly  to  the  advisability  of  its  introduc- 
tion into  practice.  It  frequently  happens  that  for  suburban 
service  a  decidedly  high  speed  of  the  car  is  necessary — for 
example,  between  fifteen  and  twenty  miles  per  hour.  Such 
speed  is  undesirable  and  would  not  be  permitted  in  the 
crowded  part  of  the  city  through  which  the  same  cars  may 
have  to  pass.  These  conditions  are  beautifully  met  by  em- 
ploying two  motors,  and  operating  them  in  parallel  for  the 
high-speed  work  and  in  series  during  the  necessarily  slower 
progress  through  the  city.  The  average  efficiency  of  the 
apparatus  can  be  very  perceptibly  raised  by  this  device,  which 


THE   EFFICIENCY    OF   ELECTRIC   TRACTION.  225 

is  already  in  use  at  several  points.  The  general  features  of 
this  case  have  been  discussed  in  Chapter  III. 

As  regards  gearing,  it  is  doubtful  if  any  device  for  trans- 
mitting the  power  from  the  armature  to  the  axle  with  a 
reduction  of  speed  can  be  made  more  efficient  and  more 
thoroughly  reliable  than  a  single  set  of  spur  gearing  running 
in  oil.  Mention  should  here  be  made  of  the  practice  of 
placing  the  armature  directly  upon  the  axle,  so  as  to  avoid 
the  use  of  gearing  altogether.  This  obviates  at  once  the 
present  losses  in  gearing,  and  thus  saves  a  very  perceptible 
amount  of  power.  Were  the  speeds  employed  on  street 
railway  lines  considerably  higher  than  they  are  at  present,  it 
would  be  a  perfectly  simple  matter  to  put  the  armature  upon 
the  axle;  and  for  railway  work  and  railway  speeds  this  is 
undoubtedly  the  best  practice,  and  has  been  followed  with 
success  in  the  City  and  South  London  Railway  inaugurated 
about  a  year  since. 

Three  types  of  gearless  motor  for  street  car  service  have 
been  brought  out  during  the  past  year,  and  have  been  em- 
ployed on  a  rather  extensive  experimental  scale.  They  are 
described  elsewhere,  in  Chapter  III.,  and  illustrate  three  rad- 
ically different  solutions  of  the  low-speed  problem. 

The  Westinghouse  gearless  motor  has  its  armature  core 
keyed  directly  to  the  axle,  without  any  attempt  at  cushioning 
of  any  kind.  . 

The  Short  gearless  motor  is  provided  with  a  cushioned 
support  quite  independent  of  the  car  axle,  with  which,  how- 
ever, the  armature  is  concentric,  but  mounted  on  a  hollow 
shaft  with  about  an  inch  clearance  all  around  the  axle.  The 
power  is  transmitted  to  the  wheels  by  driving  spiders  heavily 
cushioned  with  rubber. 

The  Eickemeyer  motor  is  flexibly  supported  midway  of 
the  truck,  and  drives  both  sets  of  wheels  by  outside  connect- 
ing-rods. 

No  tests  on  any  of  these  machines  have  been  published, 
but  the  best  data  attainable  indicate  that  the  total  commercial 
efficiency  obtained  is  no  greater  than  with  ordinary  double 
and  single  reduction  gear  machines — in  other  words,  every- 
thing that  is  gained  in  abolishing  the  gearing  is  lost  in  the 
15 


226  THE    ELECTRIC    RAILWAY. 

purely  electrical  efficiency.  The  reduction  of  the  armature- 
speed  to  as  low  as  from  100  to  1 50  revolutions  per  minute 
means  very  serious  difficulties  in  getting  up  a  counter  electro- 
motive force  to  insure  good  efficiency  and  torque  enough  to 
handle  the  cars  readily  upon  grades. 

In  none  of  the  forms  of  gearless  motor  mentioned  is  it 
entirely  evident  on  examination  how  these  two  difficulties 
are  met.  All  three  run  well  in  practice,  and  possess  the 
common  advantage  of  very  smooth  and  noiseless  operation. 
Eickemeyer  employs  one  large  motor  instead  of  two  small 
ones,  probably  gaining  thereby  electrically,  and  losing  me- 
chanically through  the  connecting-rods.  It  is  doubtful  if 
any  of  the  forms  mentioned  can  show  as  high  an  average 
efficiency  as  the  best  single-reduction  gear  motors  that  are 
now  rapidly  coming  into  use.  On  the  contrary,  it  appears 
that  the  efficiency  of  the  gearless  machines  is  less  under  the 
present  conditions  than  that  of  their  competitors.* 

They  do,  however,  enjoy  the  advantage  of  very  quiet  run- 
ning and  freedom  from  repairs  to  any  gearing  and  its  connec- 
tions, and  are  capable  of  doing  very  good  service,  provided 
they  run  under  conditions  that  insure  a  rather  high  average 
speed,  as  for  instance  in  suburban  work.  Where  two  gearless 
motors  are  employed  on  a  single  car,  their  operation  in  series 
is  decidedly  advisable,  at  ordinary  car  speeds;  with  this 
modification,  they  have  even  now  a  considerable  field  for 
usefulness.  After  the  design  of  suclr  low-speed  machines 
becomes  more  familiar  through  experience,  it  is  probable 
that  their  commercial  efficiency  can  be  raised  nearly  to  the 
value  now  possessed  by  the  single-reduction  gear  motors, 
but  up  to  the  time  of  writing  the  gearless  motors  have  not 
come  into  sufficiently  extensive  use  to  show  properly  by 
experience  their  vices  and  virtues. 

Serious  difficulties  to  be  met  in  this  case  are  those  involved 
in  regulating  devices  for  the  purpose  of  starting  and  varying 
the  speed.  In  the  City  and  South  London  Railway  a  rheostat 
is  employed,  and  this  would  also  be  fairly  successful  on  street 
cars  as,  indeed,  experiment  has  shown. 


*  A  rather  careful  approximate  test  of  one  of  the  gearless  motors  indicated  a  commer- 
c.al  efficiency  of  about  40  per  cent,  at  a  car  speed  of  between  8  and  9  miles  per  hour. 


THE    EFFICIENCY    OF    ELECTRIC    TRACTION.  22/ 

Another  solution  of  the  same  difficulty  may  be  found  in 
the  various  plans  that  have  been  devised  for  connecting  the 
armature  spindle  flexibly  with  the  axle,  so  that  the  motor 
may  run  almost  free  at  the  moment  of  starting  and  the  load 
be  assumed  gradually.  Several  varieties  of  clutch,  epicyclic 
and  hydraulic  gearing,  have  been  used  for  this  purpose.  Any 
of  them  would  dispense  with  the  steady  use  of  the  rheostat, 
and  with  the  consequent  loss  of  efficiency ;  but  at  the  expense, 
perhaps,  of  serious  mechanical  difficulties.  These  cannot  be 
told  a  priori,  and  the  use  of  such  mechanisms  has  been  up  to 
the  present  hardly  more  than  experimental.  Their  advan- 
tages cannot  be  doubted ;  and  were  a  thoroughly  practical 
apparatus  devised,  it  would  probably  find  its  way  into  very 
considerable  use. 

Summing  up,  then,  the  subject  of  motor  and  gearing  effi- 
ciency, we  find  that  from  80  to  90  per  cent,  electrical  efficiency 
is  attainable,  though  not  generally  attained  in  street  railway 
motors;  that  a  little  over  90  per  cent,  is  quite  within  reach 
in  gearing  efficiency,  and  that  all  losses  due  to  gearing  may 
be  dispensed  with  by  the  use  of  a  motor  placed  directly  upon 
the  axle.  In  the  actual  practice  of  to-day  these  efficiencies 
together  are  generally  reduced  to  less  than  75  per  cent.,  and 
often  to  between  60  and  70  per  cent. 

The  gains  that  may  well  be  made  are,  first,  a  gain  in  motor 
efficiency,  especially  in  the  low-speed  machines;  second,  a 
considerable  gain  from  the  use  of  a  single  motor ;  and  third, 
another  important  gain  in  the  use  of  only  one  set  of  gearing, 
or  its  complete  abolition.  If  a  single  motor  geared  to  both 
axles  be  employed,  about  80  per  cent,  is  the  highest  probable 
average  commercial  efficiency,  but  if  high-speed  work  over 
a  long  line  is  to  be  attempted  the  maximum  efficiency  men- 
tioned is  within  reach.  The  difficulties  inherent  in  slow 
speeds  on  street  railway  work,  however,  are  so  great  that 
only  under  extraordinary  conditions  can  high  efficiency  be 
obtained.  Better  tracks,  allowing  the  free  use  of  a  single 
motor,  and  better  all-around  construction  in  the  driving 
machinery,  are  the  means  by  which  improvements  are  to  be 
secured. 

We  are  now  in  a  position  to  sum  up  the  total  commercial 


22g  THE    ELECTRIC    RAILWAY. 

efficiency  of  electric  traction,  that  is,  the  ratio  between  the 
indicated  horse-power  at  the  station  and  the  power  actually 
delivered  at  the  car  axle.  The  two  complete  tests  referred 
to  frequently  in  this  chapter,  at  Lafayette,  Ind.,  and  Syra- 
cuse, N.  Y.,  give  respectively  25  and  37  per  cent,  as  this  final 
efficiency.  We  may,  however,  unite  the  several  efficiencies 
of  station,  line,  and  car  machinery  to  obtain  an  approximate 
figure.  Sixty-five  per  cent,  is  probably  a  high  average  for 
station  efficiency  in  the  roads  now  built.  The  line  efficiency 
may  be  taken  at  about  92  per  cent. ,  giving  a  total  efficiency 
up  to  the  motor  of  approximately  60  per  cent. 

With  the  motors  and  the  gearing  generally  employed, 
the  average  commercial  efficiency  of  the  combination  is 
probably  not  often  in  excess  of  65  per  cent.,  giving  a  total 
commercial  efficiency  for  the  system,  from  engine  to  car 
wheel,  of  39  per  cent. ;  this,  of  course,  is  but  an  estimate. 
But  taking  all  the  factors  into  consideration  it  is  probable 
that  the  average  of  the  roads  now  in  operation  would  fall 
quite  nearly  to  the  point  indicated.  In  very  few  cases  would  it 
fall  below  30  per  cent. ;  in  still  fewer  would  it  rise  much 
above  40  per  cent. 

With  regard  to  the  efficiency  that  may  be  reached  by  more 
careful  station  designing  and  better  motors,  we  can  give  but 
an  approximation.  From  the  figures  that  precede  we  may  take 
the  practicable  station  efficiency  at  75  per  cent.,  the  line  at 
95,  the  motors  at  possibly  as  high  as  90,  and  the  gearing,  if 
used,  as  averaging  about  90 ;  giving  a  possible  average  effi- 
ciency of  between  55  and  60  per  cent,  for  the  entire  system. 
Anything  over  50  per  cent,  can  be  attained  only  by  the 
utmost  care  in  design  and  construction ,  and  it  is  very  doubt- 
ful if  this  point  is  passed  by  any  line  now  operated. 

It  will  be  thus  seen  that  there  is  plenty  of  room  for  im- 
provement in  commercial  efficiency,  and  that  while  to-day 
most  electric  railroads  are  decidedly  inefficient,  it  is  practi- 
cable to  improve  them  to  a  very  considerable  extent.  Fifty 
per  cent,  in  total  efficiency  places  the  electric  roads  at  least 
on  a  par  with  most  cable  roads,  as  regards  the  question  of 
efficiency  alone,  with  the  additional  great  advantages  of  inder 
pendent  motor  units,  variable  speed,  and  the  ability  to  back. 


THE    EFFICIENCY    OF    ELECTRIC    TRACTION.  229 

Much  improvement  can  readily  be  made,  but  it  is  in  the 
mechanical  rather  than  the  electrical  parts  of  the  system  ; 
the  chief  losses,  as  we  have  already  seen,  are  in  the  station 
and  in  the  car  machinery.  The  former  may  be  obviated  by 
careful  designing  of  the  station  equipment,  the  latter  by 
improvement  in  the  mechanical  means  for  transmitting  the 
power  from  the  motor  armature  to  the  car  axle. 

No  stronger  argument  can  be  adduced  in  support  of  elec- 
tricity as  a  motive  power  than  the  fact  that,  taking  the  electric 
railway  as  it  is  to-day,  even  though  nearly  two-thirds  of  the 
power  generated  at  the  station  is  often  lost  on  the  way, 
though  the  expenses  for  repair  are  sometimes  heavy,  and 
the  first  cost  of  equipment  great,  it  still  stands  quite  unap- 
proached  as  a  method  of  cheap  and  effective  rapid  transit. 
Every  improvement  that  is  made  in  the  apparatus  means  an 
additional  advantage  for  electric  traction.  It  should  be  noted, 
too,  that  the  very  improvements  in  motors  and  gearing 
which  will  raise  the  general  efficiency  also  tend  to  diminish 
the  repair  bills. 

In  closing  this  chapter  it  should  properly  be  stated  that 
although  increase  of  general  efficiency  is  highly  to  be  desired 
and  will  result  in  a  considerable  saving,  it  must  not  be  sup- 
posed that  the  power  station  expenses,  with  which  efficiency 
has  chiefly  to  do,  are  a  very  prominent  factor  in  the  total 
operating  expenses  of  an  electric  road.  On  the  contrary,  the 
cost  of  fuel  is  in  nearly  every  case  less  than  10  per  cent,  of 
the  total  expenses  of  the  road,  so  that  the  whole  amount  that 
may  be  directly  saved  by  improvements  of  various  sorts  tend- 
ing to  increase  the  efficiency  probably  does  not  exceed  5  per 
cent,  of  the  total  operating  expenses.  This  is,  however, 
enough  to  make  the  difference  between  losing  money  and  pay- 
ing a  fair  return  on  the  investment. 


CHAPTER   VIII. 

STORAGE-BATTERY    TRACTION. 

A  CHAPTER  on  the  applicaton  of  the  storage  battery  to  elec- 
trical traction  must  of  sad  necessity  resemble  that  famous 
treatise  written  by  a  returned  sailor  on  the  manners  and 
customs  of  the  Fiji  islanders:  "Manners,  none;  customs, 
beastly." 

When  in  1880  the  voltaic  accumulator  invented  by  Plante 
about  twenty  years  previously  was  modified  into  a  more 
practical  form  and  brought  to  public  notice,  it  was  received 
with  every  symptom  of  unwonted  joy ;  for  its  advent  seemed 
to  open  a  magnificent  vista  of  electrical  energy  in  portable 
form,  ready  always  and  anywhere  to  supply  power  for  all 
sorts  of  industrial  purposes.  It  was  puffed  by  scientific 
authorities,  lauded  by  the  press,  and  vigorously  exploited  by 
the  trade. 

More  than  ten  years  have  now  passed,  and  the  promised 
land  overflowing  with  volts  and  amperes  is  still  just  beyond 
our  reach ;  not  that  the  accumulator  has  been  a  failure ;  on 
the  contrary,  it  has  been  a  partial  success ;  for,  under  favor- 
able conditions  and  for  certain  purposes,  it  has  done,  and 
will  continue  to  do,  admirable  work. 

To  define  the  storage  battery  is  not  altogether  easy ;  and 
the  distinctions  between  secondary  and  storage  cells — purely 
fanciful,  and  introduced  into  the  art  principally  for  the  pur- 
pose of  befogging  the  mind  with  legal  quibbles — have  been 
a  fruitful  source  of  misunderstanding.  Speaking  in  a  broad, 
general  way,  we  may  define  the  storage  battery  to  be  a  voltaic 
couple  of  such  materials  that  the  current-producing  chemical  re- 
actions may  be  more  or  Jess  completely  reversed  clectrolytically. 
It  differs  from  the  primary  battery  only  in  that  the  materials 
consumed  in  the  latter,  and  of  necessity  replaced  to  continue 
the  electrical  action,  may  in  the  former  be  brought  back 
nearly  to  their  initial  state  by  electrolysis. 

230 


STORAGE-BATTERY   TRACTION.  231 

As  a  matter  of  fact,  certain  primary  batteries  are  almost 
identical  in  their  chemical  properties  with  certain  storage 
batteries;  although  the  usual  form  of  accumulator  is  com- 
posed of  materials  that  cannot  be  economically  employed  in 
forming  a  primary  cell.  The  accumulator,  therefore,  is  sub- 
ject to  many  of  the  same  general  laws  as  the  ordinary  voltaic 
cell ;  it  is  coupled  up  in  precisely  the  same  way,  and  gives 
current  and  electromotive  force  not  widely  different  from 
those  of  a  primary  cell  of  similar  area  of  plates. 

It  has,  however,  the  immense  advantage  that  its  component 
materials  after  discharge  can  be  brought  back  to  nearly  their 
original  state  on  passing  a  current  through  the  cell ;  and  it  is 
this  feature  that  has  given  the  apparatus  the  name  of  storage 
battery.  The  most  familiar  form  of  accumulator  is  that  in 
which  the  voltaic  element  is  composed  of  two  lead  plates 
coated  with  oxides  of  lead  and  plunged  into  dilute  sulphuric 
acid.  Originally  the  necessary  materials  were  formed  on 
the  plates  by  electrolytic  action;  Faure,  however,  introduced 
a  so-called  pasted  cell,  in  which  two  plates  of  lead,  perforated 
or  roughened  so  as  to  permit  of  more  readily  retaining  the 
active  material,  were  coated  artificially  with  oxides  of  lead — 
one  plate  with  peroxide,  the  other  with  protoxide.  These 
oxides  mixed  with  dilute  sulphuric  acid  are  plastered  upon 
the  plates,  and,  on  drying,  the  paste  sets  firmly ;  and  the  plates 
are  then  immersed  in  the  electrolyte  ready  for  charging,  or, 
rather,  the  process  of  forming,  which  name  is  given  to  the 
preliminary  charging  and  discharging  that  is  necessary  to 
reduce  the  active  material  to  the  proper  chemical  condition 
before  it  is  put  to  real  service.  The  chemical  actions  that 
take  place  in  the  accumulator  are  very  complex  and  vary 
somewhat  with  circumstances.  Speaking  in  a  general  way, 
during  the  discharge  the  active  material  is  largely  reduced  to 
sulphate  of  lead ;  and  during  a  charge  this  is  decomposed, 
forming  on  the  one  plate  peroxide  of  lead  and  on  the  other 
reduced  lead.  This  charging  and  discharging  can  be  repeated 
over  and  over;  and  experience  has  shown  that  of  the  elec- 
trical energy  spent  in  charging  the  cell,  between  80  and  90 
per  cent,  can,  under  favorable  conditions,  be  regained  as 
electrical  energy  on  the  discharge.  The  electromotive  force 


232 


THE    ELECTRIC    RAILWAY. 


of  lead  accumulators  such  as  have  just  been  mentioned  is  in 
most  cases  when  the  cell  is  actively  beginning  its  voltaic 
action  about  2  y±  volts,  and  during  the  action  of  the  battery 
falls—slowly  at  first,  very  rapidly  after  a  time.  On  charg- 
ing, the  potential  difference  rises  rather  rapidly  until  it 


FIG.  100. -TYPICAL  STORAGE  CELL. 

reaches  about  two  volts,  and  then  more  slowly  until  it  reaches 
2.3  or  2.4  volts;  the  change  in  voltage  being  similar  to  that 
which  appears  during  the  discharge. 

The  ordinary  storage  battery  shown  in  Fig.  100  consists  of  a 
number  of  lead  plates  formed  as  just  described,  connected  in 
parallel  into  two  sets,  one  of  positive  and  the  other  of  nega- 
tive plates,  and  plunged  in  alternating  order  in  a  vessel  of 
dilute  acid.  The  plates  that  contain  the  active  material,  that 
is,  oxides  of  lead,  are  usually  reticulated  as  shown  in  Fig.  101, 
so  that  they  are  full  of  small  square  or  polygonal  cells,  in 
which  the  paste  that  forms  the  active  material  may  conven- 
iently stick.  When  the  cell  is  in  working  order,  the  process 
of  charging  converts  the  salts  of  lead  on  the  positive  plate 
into  oxide  of  lead  and  reduces  those  on  the  negative  plate,  for 
the  most  part,  to  a  somewhat  spongy  mass  of  metallic  lead. 
On  discharging,  most  of  the  material  on  both  plates  goes 


STORAGE-BATTERY    TRACTION. 


23S 


back  into  lead  sulphate.  If  it  were  possible  to  prepare 
cheaply  and  in  available  form  plates  of  peroxide  of  lead 
and  spongy  lead,  \ve  should  be  possessed  of  a  primary  battery 
in  every  respect  similar  to  the  secondary  battery  during  the 
process  of  discharging ;  as  a  matter  of  fact,  such  plates  would 
be  inconvenient  to  prepare  mechanically;  whereas  it  is  very 
handy  to  form  them  electrolytically,  by  passing  a  current 
through  the  cell  after  it  is  discharged. 

This,  in  the  rough,  is  the  principle  of  the  secondary  battery 
most  frequently  in  use  to-day.  A  large  number  of  other 
combinations  of  materials  possess  in  a  greater  or  less  degree 
the  same  power  of  forming  a  voltaic  cell  the  actions  of  which 
during  the  process  of  charging  may  be  reversed  electrolytic- 
ally  ;  and  such  combinations  form  accumulators  of  greater  or 


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FIG    101. -TYPICAL  "GRID." 

less  usefulness,  of  which  several  will  be  mentioned  further 
along  in  this  chapter. 

Having  thus  obtained  some  idea  of  the  general  character 
of  the  accumulator,  we  may  appropriately  pass  to  a  special 
consideration  of  its  application  to  practical  apparatus,  partic- 
ulary  in  electrical  traction.  Experience  has  unfortunately 
shown  that  while  these  applications  are  in  the  abstract  very- 
simple  and  beautiful,  in  practice  there  are  very  serious  inher- 
ent defects  in  the  accumulators  of  to-day — so  formidable, 
indeed,  that  the  ingenuity  of  inventors  has  been  sorely  taxed 


234  THE    ELECTRIC    RAILWAY. 

to  obtain  an  accumulator  that  shall  be  reasonably  efficient, 
moderately  reliable,  and  tolerably  durable. 

The  accumulator  gives  an  opportunity  of  utilizing  a  dynamo 
for  storing  up  chemical  energy  at  any  convenient  time  or 
place,  and  permits  it  to  be  transformed  back  again  into  elec- 
trical energy  whenever  and  wherever  desired.  The  possi- 
bility is  a  most  tempting  one,  and  immediately  the  Faure 
cell  was  brought  out  in  1880  it  was  put  to  use  for  all  sorts  of 
industrial  purposes.  When,  as  frequently  happens,  it  is 
desirable  to  obtain  light  at  times  when  no  power  is  available, 
the  accumulator  can  be  charged  whenever  an  engine  and 
dynamo  chance  to  be  running,  and  then  employed  to  supply 
electric  lamps  as  they  are  needed.  In  installations  for  the 
lighting  of  private  houses,  as  well  as  in  some  central  stations, 
it  is  very  inconvenient  to  keep  the  dynamos  in  action  all 
night ;  and  for  the  small  amount  of  service  required  during 
the  late  evening  or  after  midnight,  accumulators  can  be,  and 
are,  worked  with  a  considerable  degree  of  success.  Into  this 
field  of  work  the  accumulator  was  put  at  once,  and  has  con- 
tinued in  gradually  increasing  use  until  the  present.  It  is 
also  to  a  certain  extent  employed  for  running  small  motors, 
electro-medical  apparatus,  and  similar  very  light  work,  under 
circumstances  where  the  cell  must  be  charged  at  one  place 
and  discharged  at  another.  Eight  or  ten  years  ago  it  was 
frequently  proposed  to  have  a  central  station  occupied  ex- 
clusively with  charging  accumulators  to  be  distributed  for 
furnishing  light  and  power  to  regular  customers.  It  was 
soon  found,  however,  that  the  great  weight  of  the  batteries 
precluded  this  otherwise  very  beautiful  possibility. 

Hardly  had  electrical  traction  been  proposed,  than  it  was 
seen  that  with  a  durable  and  efficient  accumulator  most 
ideal  conditions  could  be  realized;  it  would  be  possible  to 
charge  the  batteries  at  a  point  on  the  line  where  a  power 
station  could  be  very  economically  maintained,  put  them 
into  the  cars,  and  keep  the  road  in  steady  operation,  replacing 
the  batteries  with  freshly  charged  ones  at  every  trip,  or 
whenever  the  original  set  should  become  nearly  exhausted. 

Experiments  tending  to  this  end  were  carried  out  as  early 
as  1880,  and  in  1883  a  car  was  put  into  service  at  Kew  Bridge, 


STORAGE-BATTERY    TRACTION.  235 

London ;  this  car  was  equipped  with  a  Siemens  dynamo  set 
to  run  as  a  motor,  and  under  the  seats  were  stored  fifty  large 
storage  ceils  weighing  in  the  aggregate  about  4,000  pounds. 
The  car  could  carry  over  forty  persons,  and  ran  over  its  level 
track  very  smoothly  at  the  rate  of  about  six  miles  an  hour. 

Encouraged  by  this  success,  a  considerable  number  of  ex- 
perimenters went  actively  to  work ;  and  during  the  next  two 
or  three  years  cars  were  put  into  operation  in  London,  Brus- 
sels, Paris,  and  elsewhere.  The  motors  were  as  a  rule  of 
from  4  to  8  horse-power,  and  the  weight  of  storage  battery 
varied,  according  to  the  power  supplied,  from  2,000  to  5,000 
pounds.  The  energy  stored  was 'capable  of  running  the  car 
from  thirty-five  to  fifty  miles  without  changing  the  batteries ; 
at  the  end  of  this  period  fresh  cells  had  to  be  substituted, 
and  as  these  were  of  considerable  weight  the  operation  was 
not  easy.  In  Brussels  a  number  of  accumulator  cars  were 
put  into  regular  service  about  five  years  ago.  In  this  country 
the  work  has  been  taken  up  by  several  different  companies ; 
and  during  the  last  three  years  experiments  6n  a  commercial 
scale  have  been  carried  on  in  New  York  under  the  auspices 
of  the  Julien.  Company,  which  for  a  considerable  time  oper- 
ated ten  or  twelve  cars  on  the  Fourth  Avenue  road ;  in  Phil- 
adelphia,  in  New  Orleans,  in  Washington,  and  elsewhere. 

At  the  present  time  the  accumulator  cars  in  New  York, 
Philadelphia,  New  Orleans,  and  Dubuque  have  been  aban- 
doned, and  not  a  single  road  is  to-day  commercially  operated 
in  the  United  States  by  storage  batteries.  The  nearest  ap- 
proach to  it  is  an  honest  experiment  in  Washington,  D.  C., 
the  results  of  which  are  as  yet  uncertain.*  There  are  besides 
a  number  of  experimental  cars  of  all  sorts  and  descriptions 
not  in  regular  service.  It  will  thus  be  seen  that  in  spite  of 
the  work  that  has  be"en  done,  the  results  have  not  been  alto- 
gether satisfactory.  It  is  worth  while  looking  in  detail  into 
the  matter  for  the  purpose  of  seeing  what  the  trouble  has 


*  We  make  this  statement  advisedly,  since  not  even  one  road,  so  far  as  reported,  is 
operated  independently  of  the  storage-battery  companies.  No  safe  commercial  conclu- 
sions can  be  drawn  from  cars  that  are  continually  under  the  supervision  of  skilled  elec- 
tricians employed  by  the  installing  and  not  by  the  operating  company. 


THE   ELECTRIC    RAILWAY. 


been,  and  if  possible  forming  some  idea  as  to  the  outlook  for 
better  results  in  the  future. 

Much  ingenuity  has  been  expended  in  working  out  the  de- 
tails of  storage-battery  traction;  almost  every  conceivable 
form  has  been  given  to  the  lead  plates  intended  to  hold  the 
active  material;  several  of  these  are  shown  in  Figs.  102  and 
103.  The  intent  has  been  to-  secure  a  light  supporting  struct- 
ure capable  of  holding  the  plugs  of  active  material  very 
firmly.  *  The  cells  used  on  cars  are  almost  universally  placed 
in  trays  under  the  seats,  and  either  slid  out  endwise  or  taken 
out  sidewise  by  lifting  up  doors  at  the  sides  of  the  car.  One 


\ 


FIG.  102.— SPECIMEN  GRIDS. 

very  neat  and  successful  arrangement  for  accomplishing  this 
has  been  in  use  in  connection  with  the  Julien  cars  on  the 
Fourth  Avenue  road  in  New  York,  and  is  shown  in  Fig.  104. 
It  consists,  as  will  be  seen,  of  something  very  like  a  dumb 
waiter  with  several  shelves  placed  on  either  side  of  a  space 
just  wide  enough  to  permit  the  car  to  run  in.  The  car  is 
brought  between  the  two  series  of  shelves,  the  exhausted  bat- 


*  It  is  unfortunate  that  lead,  the  only  cheap  metal  capable  of  resisting  the  attacks  of 
sulphuric  acid,  is  so  undesirable  from  a  mechanical  point  of  view,  and  so  heavy.  If  the 
plugs  of  active  material  are  in  intimate  contact  with  the  grid  they  are  almost  certain  by 
change  in  volume  to  warp  the  weak  lead  support,  while  it  is  difficult  to  "take  up" 
expansion  without  encountering  electrical  difficulties. 


STORAGE-BATTERY    TRACTION. 


237 


teries  shoved  out  on  the  empty  shelves,  and  the  dumb  waiters 
lowered  so  that  fresh  trays  of  charged  accumulators  can  be 


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FIG.  103.— SPECIMEN  GRIDS. 

thrust  into  place.  The  operation  can  be  very  expeditiously 
performed  by  this  means.  Some  very  ingenious  special  reg- 
ulating devices  are  employed,  both  in  the  station  and  on  the 


238 


THE    ELECTRIC    RAILWAY. 


cars ;  and  in  the  latter  case  the  power  possessed  in  storage- 
battery  traction,  of  using  more  or  less  cells  on  the  motor,  as 
required,  enables  the  latter  to  be  used  in  a  quite  economical 
way — rather  more  efficiently,  doubtless,  than  the  ordinary 
machines  where  regulation  is  effected  by  a  rheostat  or  by  field 
commutation. 

The  motors  for  storage-battery  use  are  almost  always  de- 
cidedly less  powerful  than  those  generally  employed  in  the 
direct  systems  of  supply,  for  the  very  good  reason  that  to 


FIG.    I04—APPARATUS   FOR   REPLACING  THE   BATTERIES  ON    A   CAR. 

carry  batteries  enough  to  supply  continuously  an  amount  of 
power  equivalent  to  that  used  on  the  ordinary  electric  rail- 
way is  at  present  almost  out  of  the  question  ;  and,  furthermore, 
is  unnecessary,  because  storage-battery  cars  are  not  well  fitted 
for  work  on  severe  grades,  for  reasons  which  will  be  ex- 
plained presently. 

There  is  little  that  is  unusual  in  the  appearance  of  electric 
cars  fitted  with  storage  batteries ;  the  only  thing  to  be  re- 
marked is  the  absence  of  the  trolley  or  any  visible  collecting 
device,  and  sometimes  a  slight  widening  of  the  lower  body 
of  the  car  for  the  sake  of  receiving  the  batteries.  Altogether 


STORAGE-BATTERY    TRACTION.  239 

the  experiments  with  storage-battery  traction  have  met  with 
only  partial  success ;  for  reasons  not  for  the  most  part  de- 
pendent on  any  lack  of  care  or  skill  on  the  part  of  those  who 
have  engineered  the  various  attempts,  but  on  account  of 
defects  inherent  in  the  batteries — not  confined,  as  a  rule,  to 
any  particular  type,  but  common  to  the  entire  class.  As 
long  as  an  accumulator  car  is  favored  with  expert  care  and 
handled  with  great  judgment  and  discretion  it  is  likely  to 
operate  well,  and,  so  far  as  successful  running  is  concerned, 
to  compare  favorably  with  any  other  form  of  automobile  car. 

When  these  conditions  are  not  fulfilled,  the  time  comes 
when  the  storage  batteries  exhibit  deterioration,  they  are  not 
properly  replaced,  and  failure  is  the  uniform  result.  To 
investigate  the  difficulties  that  have  interfered  with  the  de- 
velopment of  storage-battery  traction  we  must  begin  with 
the  root  of  all  the  evils  that  befall  them,  that  is,  with  the 
accumulator  itself. 

Following  the  classification  adopted  by  M.  Reynier  we  may 
divide  accumulators  into  four  genera,  first,  the  lead  and  sul- 
phuric acid  genus,  including  the  original  Plante  cell — which, 
by  the  way,  is  not  to  be  despised,  even  to-day — and  the 
Faure  cell  with  all  its  modifications,  including  the  great  bulk 
of  accumulators  that  are  in  use.  Second,  the  lead-copper 
genus,  consisting  practically  of  plates  coated  with  lead  oxide 
immersed  together  with  copper  negative  electrodes  in  a  solu- 
tion of  sulphate  of  copper;  these  are  not  used  in  anything 
more  than  an  experimental  way,  and  are  simply  interesting 
theoretically.  Third,  a  very  similar  cell  composed  of  lead 
positive  plates,  zinc,  and  sulphate  of  zinc,  which  possesses 
an  electromotive  force  slightly  higher  than  the  ordinary  lead 
cell  and  has  a  high  capacity  in  proportion  to  its  weight,  but 
is  open  to  the  serious  fault  of  losing  part  of  its  charge  on 
open  circuit,  and  shares  many  of  the  inherent  defects  of  the 
ordinary  Plante  type.  Fourth,  the  alkaline  zincate  genusr 
the  analogue  of  the  Lalande-Chaperon  battery,  better  known 
in  this  country  in  its  modified  form  of  the  so-called  Edison- 
Lalande  cell. 

In  this  case  the  positive  plate  is  of  porous  copper,  the 
negative  plate  iron — often  gauze — and  the  liquid  sodium  or 


240 


THE    ELECTRIC    RAILWAY. 


potassium  zincate.  This  type  of  cell  has  some  admirable 
properties  and  has  been  applied  to  traction  with  tolerable 
results,  although  not  yet  in  use  long  enough  to  justify  any- 
thing like  a  final  judgment  as  to  its  merits.  The  first  genus 
contains  nearly  all  the  species  in  practical  use,  their  differ- 
ences being  mainly  constructional.  The  reactions  are  about 
the  same  in  all,  and  the  defects  the  same  in  kind,  differing 
only  in  degree.  If  it  were  possible  to  make  the  chemical 
action  in  an  accumulator  perfectly  reversible,  we  should  be 
possessed  of  an  invaluable  adjunct  in  all  electrical  operations, 
but  unfortunately  this  is  not  the  case.  The  fundamental 
difficulty  is  one  not  confined  to  the  accumulator,  but  one 
inherent  in  nearly  all  chemical  reactions  that  are  at  all  com- 
plicated. It  is  generally  true  that  all  except  the  simplest 
reactions  are  not  quantitative  in  character;  that  is,  more  or 
less  material  is  converted  into  a  form  that  cannot  be  utilized, 
or  by-products  are  produced  in  greater  or  less  quantity. 

The  amount  and  character  of  the  by-products  is  very  largely 
regulated  by  the  speed  or  the  temperature  at  which  the  reac- 
tion is  carried  on  ;  it  often  happens  that  a  slow  reaction  and 
a  rapid  one,  albeit  of  the  same  general  character,  lead  to 
different  results.  Theoretically,  the  chemistry  of  the  storage 
battery  is  that  which  has  been  already  stated — a  reduction 
during  discharge  of  oxides  of  lead  on  the  positive  plate,  with 
the  formation  of  lead  sulphate  on  both  plates.  During  the 
charge,  the  .lead  sulphate  is  decomposed  electrolytically, 
forming  lead  oxide  on  the  positive  plate  and  spongy  lead  on 
the  negative  plate ;  unfortunately  this  is  not  what  is  known 
to  chemists  as  a  "clean"  reaction.  On  the  discharge,  free 
oxygen  and  hydrogen  are  formed  in  the  solution,  together 
with  ozone  and  hydrogen  peroxide,  that  attack  the  plates 
without  materially  assisting  in  the  production  of  the  cur- 
rent. 

There  is  local  action  of  a  useless  and  injurious  character 
between  the  support  of  the  active  material  and  the  different 
parts  of  the  active  material  itself.  Other  and  more  compli- 
cated* substances — basic  sulphates  of  lead,  and  the  like — are 
also  produced  in  the  cell ;  besides  these  there  is  the  inevitable 
heating  owing  to  ohmic  resistance,  and  losses  due  to  over- 


STORAGE-BATTERY    TRACTION. 


24I 


charging;  and  among  all  these  from.  10  to  15,  or  even  as 
high  as  30  to  40,  per  cent,  of  the  energy  may  be  lost  in  the 
process  of  charging  and  discharging,  the  amount  depending 


2357  1O    HOURS   10  2O  25 

FIG.  105.— CURVES  SHOWING  VARIATION  OF  CAPACITY  WITH  DISCHARGE  RATE. 

largely  on  the  rate  at  which  the  reactions  go  on — the  faster 
the  charge   and    discharge,    the  more    by-products  and   the 
lower  efficiency. 
16 


242 


THE   ELECTRIC    RAILWAY. 


In  fact,  the  capacity  of  the  battery,  that  is,  the  amount  o* 
electrical  energy  it  is  capable  of  giving  out,  is  a  function 
of  the  rate  of  discharge,  as  well,  of  course,  as  of  the  rate  of 
charge.  In  some  forms  of  storage  cell  this  relation  is  almost 
linear,  so  that  if  a  given  accumulator  has  a  storage  capacity  of 
60  ampere  hours  at  a  discharge  rate  of  10  amperes,  it  will  have 
a  capacity  of  but  30  when  20  amperes  are  continuously  drawn 
from  it.  Fig.  105  shows  a  curve  taken  from  a  particular  type 
of  cell  that  has  been  used  extensively,  showing  admirably 
the  disastrous  effect  of  attempting  to  force  the  discharge  rate. 

The  losses  incurred  may  be  divided  into  four  groups :  first, 
the  direct  losses  due  to  heating ;  second,  losses  due  to  local 
action  between  the  active  material  and  the  supporting  grids ; 
third,  the  losses  due  to  local  action  in  the  active  material ; 
and,  fourth,  losses  due  to  unreversed  chemical  action.  These 
various  factors  possess,  in  different  types  of  cells,  and  in  the 
same  cell  under  different  conditions,  very  different  relative 
values.  The  last  two  sources  of  loss  are  intimately  con- 
nected with  each  other  and  are,  on  the  whole,  generally  the 
most  formidable.  Of  the  irreversible  action  a  portion  is  due 
to  the  formation  of  irreversible  compounds,  and  another  por- 
tion to  the  electrolytic  action  producing  free  hydrogen  and 
oxygen,  ozone,  and  hydrogen  peroxide.  The  formation  of 
the  latter  substances  does  not  tend  permanently  to  deteriorate 
the  cell,  while  a  portion  at  least  of  the  former  compounds 
are  of  such  a  character  as  to  damage  the  cell  in  a  way  that 
cannot  well  be  repaired.  Thick  grids,  with  plugs  of  active 
material  of  corresponding  thickness,  are  particularly  likely 
to  suffer  from  the  various  difficulties  mentioned — with  the 
exception  of  the  pure  heating  effect — because  the  chemical 
action  in  a  large  and  dense  mass  of  material  is  anything  but 
uniform  throughout  its  volume,  and  potential  differences  are 
undoubtedly  set  up  between  different  portions  of  the  same 
plug. 

Aside  from  these  chemical  defects  of  the  lead  storage  bat- 
tery there  are  others  of  a  mechanical  nature.  Chief  among 
these  may  be  mentioned  the  well-known  and  very  serious 
buckling,  to  which  the  positive  plates  in  particular  are  very 
subject;  the  cause  is  the  expansion  and  contraction  of  the 


STORAGE-BATTERY    TRACTION.  243 

plugs  during  charge  and  discharge.  This  is  to  a  considerable 
extent  unavoidable,  although  efforts  have  been  made  with 
considerable  success  to  eliminate  its  ill  effects  by  so  forming 
the  plug  as  to  permit  of  expansion  in  its  own  plane,  thereby 
partially,  at  least,  avoiding  any  tendency  toward  lateral  dis- 
tortion. The  final  result  of  buckling  is  a  short  circuit  and 
rapid  destruction  of  the  battery.  Aside  from  this,  some  of 
the  lead  sulphate  formed  during  discharge  is  very  frequently 
lost,  falling  down  into  the  bottom  of  the  jar  and  thereby  being 
put  out  of  useful  action.  At  very  rapid  discharge  rates,  too, 
there  is  a  strong  tendency  toward  disintegration  of  the  plugs 
of  active  material.  Sometimes  this  action  is  very  violent, 
producing  radiating  cracks  from  the  center  of  the  plug,  al- 
most as  if  explosive  force  were  at  work  from  a  point  within. 

Aside  from  all  this,  the  lead  accumulator  is  heavy;  the 
total  weight  per  horse-power  hour  of  energy  stored  is  in  most 
types  from  100  to  125  pounds.  By  employing  thin  plates  of 
active  material  upon  unusually  light  supporting  grids  consid- 
erably lighter  cells  have  been  formed,  giving  i  horse-power 
hour  of  output  on  approximately  50  to  75  pounds  total  weight, 
but  these  light  cells  have  by  experience  been  found  to  be 
too  fragile  to  stand  the  wear  and  tear  of  continued  use,  and 
have  consequently  been  generally  abandoned  except  for  ex- 
perimental purposes.  From  what  has  already  been  said  it  will 
be  easily  understood  that  a  very  high  discharge  rate  means 
decreased  capacity,  and  hence  a  greater  necessary  weight 
of  accumulator  per  horse-power  hour  stored.  The  figures 
given  are  for  the  so-called  normal  discharge  rates,  running 
usually,  in  the  sizes  of  cells  ordinarily  employed,  from  10  to 
30  amperes.  Of  course  the  limiting  factor  in  the  weight  of 
battery  necessary  is  the  practicable  discharge  rate.  So  much 
for  the  general  properties  of  the  lead  accumulator. 

The  second  and  third  genera  of  accumulators  mentioned 
previously  have  not  come  into  commercial  use,  and  there  are 
no  signs  of  their  development.  The  alkaline  zincate  cell, 
however,  has  very  recently  come  to  the  front,  and  has  accom- 
plished some  excellent  work.  The  starting  point  of  this  cell, 
as  previously  mentioned,  was  the  Lalande-Chaperon  primary 
battery, which  was  composed  of  an  agglomerated  plate  of  oxide 


244  THE    ELECTRIC    RAILWAY. 

of  copper,  a  zinc  plate,  and  a  solution  of  caustic  potash.  The 
action  in  this  cell  is  the  gradual  consumption  of  the  zinc, 
and  the  reduction  of  the  copper  oxide  to  metallic  copper 
through  the  agency  of  the  oxygen  set  free.  The  oxide  of 
copper  serves,  then,  as  the  depolarizing  agent.  Lalande  and 
Chaperon  discovered  the  fact  that  this  form  of  cell  was 
reversible,  although  they  did  very  little  to  elaborate  it. 

In  the  hands  of  MM.  Commelin,  Desmazures  and  Bailhache 
the  Lalande-Chaperon  battery  was  developed  into  a  quite 
efficient  accumulator.  The  positive  electrodes  of  this  battery 
are  composed  of  porous  copper  plates  formed  by  the  com- 
pression of  finely  divided  electrolytic  copper  upon  a  nucleus 
of  copper  gauze ;  the  negative  electrodes  are  made  of  amal- 
gamated, tinned,  iron  wire  gauze;  the  positive  electrodes  are 
surrounded  by  parchment-paper  cells,  the  office  of  which  is 
supposed  to  be  to  prevent  any  cupric  oxide — which  is  slightly 
soluble  in  caustic  alkalies,  but  does  not  dialyze  readily — from 
becoming  mixed  with  the  potassium  zincate ;  the  resulting 
accumulator  is  converted  by  charging  into  what  is  virtually  a 
Lalande-Chaperon  primary  cell.  It  possesses  under  discharge 
the  low  electromotive  force  of  only  about  .8  of  a  volt  per 
couple,  but  nevertheless  has  a  high  weight  efficiency,  50  to  75 
pounds  being  the  total  weight  required  for  I  horse-power 
hour  of  output. 

These  batteries  were  employed  with  success  in  some  ex- 
periments on  submarine  torpedo  boats  carried  out  under  the 
auspices  of  the  French  Government,  noticeably  in  the  exceed- 
ingly interesting  trials  of  the  torpedo  boat  La  Gymnotc,  in 
the  harbor  of  Toulon.  The  type,  however,  has  not  come  into 
general  use  as  yet. 

The  efficiency  appears  to  be  just  about  the  same  as  that 
of  lead  accumulators;  but  practical  trials  like  the  one  just 
mentioned  showed  that  on  forcing  the  output,  there  was, 
as  there  is  in  lead  accumulators,  considerable  loss  due  to- 
irreversible  action,  and  a  certain  tendency  to  disintegration. 
The  chemistry  of  the  cell,  however,  has  not  been  sufficiently 
studied  to  enable  the  exact  character  of  these  losses  to  be 
definitely  ascertained.  The  weight  is  about  the  same  as  that 
of  the  lightest  types  of  lead  battery.  The  alkaline  zincate 


STORAGE-BATTERY    TRACTION. 


24$ 


cell,  however,  is  of  somewhat  greater  volume  for  equal  out- 
put, though  doubtless  of  greater  strength  and  somewrhat 
greater  duration  of  life  than  lead  batteries  of  the  same 
weight  efficiency.  It  has  been  desirable  to  go  somewhat  into 
detail  in  regard  to  this  matter,  inasmuch  as  this  type  of  cell 
has,  in  the  hands  of  three  American  inventors,  Messrs.  Wad- 
dell,  Entz,and  Phillips,  undergone  some  modifications,  and  has 
been  applied  by  them  with  fairly  good  results  to  electric  trac- 
tion. The  form  of  electrodes  they  have  employed  is  shown  in 
Fig.  1 06.  The  positive  plates  are  composed  of  a  folded  porous 
copper  wire,  having  a  solid  nucleus  and  surrounded  with  a 
woven  envelope  to  serve  a  purpose  similar  to  the  function  of 
the  parchment-paper  cell  in  the  French  form  of  battery. 
The  negative  plate  is  of  iron,  and  the  weight  efficiency  and 
general  efficiency  of  the  battery  seem 
to  be  about  the  same  as  those  of  its 
prototype ;  but  how  far  the  difficulties 
of  unsatisfactory  life  of  the  plates, 
irreversible  action  at  high  discharge 
rates,  running  down  on  open  circuit, 
and  short  circuits  from  a  growth  of 
"zinc  tree, "have  been  avoided,  only 
time  can  show. 

Taking  up,  now,  the  application  of 
the  storage  battery  to  the  specific 
problem  of  electric  traction,  one  is  at 
once  confronted  by  the  very  consider- 
able weight  of  accumulators  abso- 
lutely necessary  in  the  present  state 
of  the  art  to  secure  continued  ser- 
vice. The  experience  of  a  very  large  number  of  electric- 
roads  extending  over  several  years  has  shown  that  the  work 
required  per  car  mile  on  ordinary  16  or  18  foot  cars  is  a 
little  below  i  horse-power  hour;  at  the  car  perhaps  three- 
fourths  of  a  horse-power  hour  is  generally  sufficient ;  this 
for  ordinary  grades  and  the  usual  rates  of  speed  of  from  eight 
to  ten  miles  per  hour.  We  can  therefore  form  a  very  good 
idea  of  the  amount  of  stored  energy  that  must  be  carried  for 
ordinary  service  on  an  accumulator  road.  Assuming  the 


FIG.   106.  —  POSITIVE  PLATE    OF 
ALKALINE  ACCUMULATOR. 


246  THE    ELECTRIC    RAILWAY. 

.average  car  mileage  per  day  at  100,  which  is  very  nearly  the 
mean  of  the  roads  now  running,  one  sees  immediately  that 
the  weight  of  batteries  carried  for  an  all-day  run  would  have 
to  be  in  the  vicinity  of /, 500  pounds.  Ordinarily  it  has  been 
the  practice  to  change  the  batteries  two  or  three  times  a  day, 
but  this  smaller  battery  power  carried  means,  as  has  already 
been  seen,  on  attempting  to  force  the  output  for  certain  emer- 
gencies, a  considerably  diminished  storage  capacity,  so  that 
it  has  been  found  practically  necessary  to  provide  from  3,500 
to  4,500  pounds  of  battery  for  the  regular  service  of  a  car. 

This  dead  weight  is  carried  about  continuously.  The  single 
car  that  has  been  experimentally  operated  with  alkaline 
^incate  batteries  has  considerably  reduced  this  figure,  carry- 
ing only  about  2,500  pounds  of  battery,  as  might  be  antici- 
pated from  the  greater  weight  efficiency ;  but  it  has  not  at 
the  time  of  writing  been  in  service  long  enough  to  permit  a 
fair  judgment  of  the  results.  As  a  matter  of  fact,  the  effect 
of  forced  output  on  batteries  in  such  service  is  at  times  so 
great  that  even  the  weights  of  battery  mentioned  are  not 
designed  to  furnish  the  power  ordinarily  used  on  overhead 
electric  roads;  in  other  words,  most  of  the  storage-battery 
cars  that  have  been  operated  in  this  country  and  elsewhere 
have  secured  reduced  weight  of  battery  by  skimping  on  power. 

A  very  brief  computation  founded  on  a  catalogue  of  stor- 
age batteries  will  show  that  to  produce  the  10  or  15  horse- 
power necessary  on  even  quite  moderate  grades,  either  a 
weight  of  battery  considerably  in  excess  of  that  mentioned 
muct  be  carried,  or  the  discharge  rate  must  reach  a  point 
very  considerably  above  that  for  which  the  rated  capacity  of 
the  cells  is  given.  There  is  really  no  occasion  for  carrying 
battery  power  enough  for  long  runs,  for  batteries  can  be 
changed  just  as  horses  are ;  the  difficulty  is,  however,  that  a 
battery,  even  if  charged  every  trip,  must  be  capable  of  a  cer- 
tain maximum  rate  of  output;  and  this  at  present  entails  the 
use  of  heavy  batteries,  however  often  they  are  changed. 
The  weight  of  accumulators  to  be  carried  can  only  be  mate- 
rially decreased  by  securing  a  higher  efficient  discharge  rate. 

It  is  readily  understood  that,  in  electric  traction,  in  starting 
a  car,  and  on  curves  and  grades,  there  is  always  violent  de- 


STORAGE-BATTERY    TRACTION.  2/1/ 

mand  for  current,  lasting  anywhere  from  a  few  seconds  to 
several  minutes,  and  demanding  from  the  battery,  if  one  is 
used,  an  especially  heavy  output.  Every  such  call  for  a 
large  current  tends  to  lessen  the  efficiency  and  life  of  the  cell, 
so  that  while  in  the  laboratory  the  storage  battery  can  be 
worked  to  nearly  90  per  cent,  efficiency — a  figure  which  can 
be  approximated  in  electric-light  service — for  traction  pur- 
poses this  percentage  must  be  much  reduced.  Naturally, 
those  most  immediately  interested  are  very  chary  about  giv- 
ing details  as  to  commercial  efficiency ;  but  from  the  best 
sources  of  information  obtainable,  the  results  of  experiments 
on  a  considerable  scale  with  storage-battery  cars,  one  is  jus- 
tified in  concluding  that  in  every-day  traction  work  the  mean 
efficiency  of  the  cell  is  probably  between  60  and  70  per  cent. 
— in  some  cases  even  lower.  Seventy  per  cent,  is  certainly 
a  favorable  estimate  for  the  battery;  and  this  lowered  effi- 
ciency means  also  a  lowered  weight  efficiency,  hence  more 
frequent  changes  of  battery  or  a  greater  amount  carried. 

If  it  were  not  for  the  great  weight  of  battery  the  low 
efficiency  could  be  tolerated,  but  the  result  is  a  considerable 
increase  in  the  dead  weight  that  must  be  carried  about;  and 
dead  weight  in  an  automobile  street  car  of  any  pattern  is  an 
unmitigated  objection.  The  two  tons  of  battery  placed  in  a 
car  require  a  very  much  stronger  structure  than  would  other- 
wise be  necessary;  and  although  the  motors  employed  in 
storage-battery  work  are  usually  lighter  than  those  used  in 
the  systems  of  direct  supply,  for  the  reason  that  it  is  intended 
to  supply  less  power,  the  total  weight  of  the  car  equipment 
is  brought  up  to  a  figure  unpleasantly  high.  A  standard  16- 
foot  car,  with  its  two  15 -horse-power  motors,  weighs  about 
five  tons;  while  the  storage-battery  cars  of  the  ordinary  pat- 
tern such  as  have  been  used  on  the  Fourth  Avenue  road  in 
New  York  weighed  about  seven  tons,  of  which  3,600  to  3,800 
pounds  was  battery. 

The  carrying  capacities  of  the  two,  however,  are  practi- 
cally equal;  so  that,  per  unit  of  useful  work,  the  necessary 
supply  of  power  required  in  the  direct  and  the  storage  sys- 
tems of  supply  is  in  the  ratio  of  five  to  seven.  With  a  sim- 
ilar motor  equipment,  that  is,  the  same  capacity  for  doing 


248  THE    ELECTRIC    RAILWAY. 

work,  the  ratio  would  be  about  four  to  seven.  That  the  two 
tons  of  extra  weight  carried  about  by  storage-battery  cars 
means  a  considerable  disadvantage  in  the  matter  of  power, 
is  a  question  that  admits  of  but  one  answer.  With  the 
ordinarv  co-efficient  of  traction  of  about  twenty  pounds  per 
ton  and  a  car  speed  of  eight  miles  per  hour,  the  additional 
power  continuously  needed  to  drag  around  the  storage  battery 
amounts  to  nearly  i  horse-power;  this  figure  is. for  a  level 
track ;  if  grades  are  to  be  attempted  in  addition,  the  additional 
power  required  would  be  a  little  less  than  i  horse-power  for 
each  per  cent,  of  grade. 

As  regards  the  actual  commercial  efficiency  of  traction  by 
storage  batteries,  it  is  not  unfair  to  say  that  the  systems  of 
direct  supply  have  at  least  the  advantage  consequent  on  less 
power  needed  for  unit  useful  work.  In  the  station,  the  stor- 
age-battery road  has  somewhat  the  advantage;  because  the 
dynamos  are  of  the  same  efficiency  in  either  case,  while  in 
charging  batteries  both  dynamos  and  engines  can  be  worked 
at  an  approximately  regular  load  and  near  the  point  of  maxi- 
mum efficiency.  Taking  the  friction  of  the  engine  at  about 
10  per  cent,  of  its  rated  full  load,  which  is  an  estimate  in 
accordance  with  the  facts,  the  efficiency  from  steam  to  elec- 
trical energy  at  the  charging  station  may  be  reasonably  taken 
as  about  75  per  cent. 

This  is  something  like  TO  per  cent,  better  than  is  likely  to 
be  obtained  on  any  but  the  very  best  overhead  systems. 
The  efficiency  of  the  motors  will  not  vary  widely  in  the 
two  cases,  although  the  regulation,  by  changing  the  grouping 
of  the  batteries — which  is  readily  accomplished  in  the  storage 
system — gives  it  a  slight  advantage.  Another  small  gain 
may  be  secured  by  using  the  motors  as  dynamos  to  restore  a 
certain  amount  of  energy  to  the  batteries  during  the  opera- 
tion of  stopping  the  car.  To  offset  this  we  have  on  the  one 
hand  loss  in  the  line,  on  the  other  the  inefficiency  of  the 
battery;  the  former  is  somewhere  in  the  vicinity  of  10  per 
cent. ;  the  efficiency  of  the  battery,  as  just  mentioned,  is 
hardly  likely  to  rise  above  70  per  cent.,  and  is  more  probably 
below  this  figure.  So  that,  taken  altogether,  we  find  that 
the  storage  battery  in  station  and  motors  gains  perhaps  1 5 


STORAGE-BATTERY    TRACTION.  349 

per  cent,  in  efficiency,  and  loses  between  20  and  25  per  cent, 
in  the  comparison  between  losses  in  battery  and  losses  in 
line.  As  a  net  result,  the  total  commercial  efficiency  from 
indicated  horse-power  at  the  engine  to  brake  horse-power  at 
the  wheel  is  probably  nearly,  or  quite,  10  per  cent,  less  than 
in  the  system  of  direct  supply.  A  similar  figure  may  be 
reached  ,by  considering  in  detail  the  efficiency  of  the  series 
of  transformations  that  occur  in  a  storage-battery  plant. 

Taking  the  efficiency  of  the  station  at  75  per  cent,  and  the 
commercial  efficiency  of  the  motors  at  the  same  high  figure, 
and  combining  these  with  the  efficiency  of  the  batteries — 
estimated  at  70  per  cent. — the  total  commercial  efficiency  of 
the  system  appears  to  be  about  40  per  cent. ;  while  the  various 
tests  made  on  the  very  best  direct  systems  indicate  a  total 
commercial  efficiency  of  a  trifle  under  50  per  cent. 

Aside  from  this,  we  still  have  the  greater  power  re- 
quired on  account  of  carrying  around  the  batteries,  which  is 
of  the  magnitude  previously  stated ;  this  latter  disadvantage 
could  be  for  the  most  part  obviated  if  it  were  possible  to 
obtain  a  light  storage  battery.  In  the  storage  car  using 
the  alkaline  zincate  batteries  the  total  weight  of  car  and 
batteries  is  just  about  the  same  as  that  of  the  standard  motor 
car  of  the  ordinary  sort,  although  the  power  supplied  is  not 
equivalent  in  the  two  cases. 

To  find  the  relative  commercial  availability  of  the  storage 
system,  various  other  factors  in  the  expense  must  be  con- 
sidered. 

Accumulator  traction  undoubtedly  has  the  advantage  of 
requiring  a  smaller  expenditure,  and  hence  smaller  interest 
charges,  at  the  central  station.  From  the  regular  way  in  which 
the  dynamos  and  engines  can  be  operated  the  capacity  of  the 
charging  station  may  be  reduced  to  one-half,  or  at  all  events 
to  two-thirds,  that  required  for  operating  the  same  number 
of  cars  by  direct  supply.  On  the  other  hand,  we  have  to 
consider  the  relative  cost  of  the  equipment  and  maintenance 
of  the  battery  and  of  the  overhead  system  necessary  for  dis- 
tribution. In  the  first  cost  the  ratio  between  them  will 
depend  on  the  number  of  cars  per  mile  operated  by  the  over- 
head wires,  for  the  battery  charges  in  the  accumulator  service 


2r0  THE    ELECTRIC    RAILWAY. 

vary  almost  directly  with  the  number  of  cars.  With  direct 
supply  the  cost  of  the  distributing  system  increases  a  little 
more  rapidly  than  the  mileage  when  the  number  of  cars  is 
uniform.  In  a  long  run  with  few  cars  the  advantage  would 
unquestionably  be  on  the  side  of  the  storage  battery; 
on  a  line  with  a  large  number  of  cars,  quite  in  the  other 
direction. 

As  regards  cost  of  maintenance  the  subject  is  open  to  no 
debate  whatever.  If  an  overhead  system  is  properly  put  up 
it  depreciates  but  slightly ;  5  per  cent,  per  annum  would  be 
a  large  estimate,  while  3  per  cent,  would  cover  it  in  many 
cases.  The  depreciation  of  the  batteries  is  an  indeterminate 
quantity,  but  is  undoubtedly  large.  Figures  on  this  point 
are  hard  to  find,  for  there  is  a  very  wide  discrepancy  between 
the  estimates  of  the  makers  on  the  depreciation  of  a  given 
battery  and  the  results  found  when  it  is  put  in  service  for 
traction  purposes.  There  have  been  so  few  storage -battery 
roads  operated,  and  of  these  so  few  have  given  to  the  public 
any  definite  report,  that  the  question  is  a  puzzling  one. 

When  the  storage  system  in  Brussels  was  abandoned  as  more 
costly  than  traction  by  horses,  after  two  years'  experience, 
it  was  stated  that  the  life  of  the  positive  plates  was  about  two 
hundred  days,  that  of  the  negative  plates  considerably  longer. 
An  extensive  experience  in  this  country  with  batteries  used 
in  lighting  railway  trains — a  far  less  severe  service  than 
traction — showed  that  the  positive  plates  were,  as  a  rule, 
destroyed  within  a  year.  In  Brussels  the  cost  of  maintenance 
of  the  batteries  proved  to  be  2^  cents  per  car  mile. 

A  very  recent  report  from  Birmingham,  England,  where 
the  storage  battery  has  been  given  a  pretty  careful  trial, 
showed  the  cost  of  maintenance  for  a  total  car  equipment  to 
be  4  cents  per  car  mile.  The  result  of  our  present  experi- 
ence with  systems  of  direct  supply  seems  to  show  that  the 
maintenance  of  motor  and  car  apparatus  amounts  to  between 
i  and  2  cents  per  car  mile— under  favorable  conditions,  near 
the  former  figure.  Assuming  this  amount  as  a  fair  estimate 
for  the  Birmingham  line,  we  reach  about  3  cents  per  car  mile 
as  the  cost  of  the  maintenance  of  batteries  in  that  case.  One 
of  the  American  storage-battery  companies  recently  estimated 


STORAGE-BATTERY    TRACTION.  2$  I 

the  maintenance  of  the  storage-battery  equipment  at  $700 
per  year  per  car.  This  is  probably  low,  as  in  Brussels  the 
contracting  company's  estimate  for  a  similar  type  of  battery 
was  il/8  cents  per  car  mile  instead  of  the  2^  cents  actually 
found.  Reports  from  the  late  Dubuque,  la.,  road  gave  the 
life  of  the  batteries  at  much  less  than  a  year.  All  this  would 
indicate  a  maintenance  account  of  dangerously  near  100  per 
cent,  per  annum — certainly  over  50  per  cent. — an  amount 
far  in  excess  of  the  depreciation  in  overhead  lines  and  motors 
on  the  trolley  system. 

We  are  therefore  driven  to  the  conclusion  that,  considering 
everything,  the  storage-battery  method,  at  present,  is  de- 
cidedly more  expensive  than  the  usual  system  of  electric 
traction,  and  that,  unless  the  batteries  are  substantially  im- 
proved in  duration  of  life,  it  is  likely  to  remain  so.  Never- 
theless, this  conclusion  does  not  prove  that  the  storage  battery 
cannot  now  and  then  be  applied  under  favorable  conditions. 
Two  years  ago  the  experience  in  Brussels  showed  that  its 
cost  was  greater  than  that  of  traction  by  horses,  while  the 
recent  report  from  Birmingham  shows  a  small  balance  on 
the  other  side  of  the  account. 

There  is  a  very  strong  prejudice  against  the  use  of  over- 
head wires  in  large  cities,  and  if  electric  traction  is  to  be 
introduced  under  such  circumstances  the  choice  lies  between 
conduits  and  storage  batteries.  The  former  will  be  taken  up 
in  a  later  chapter ;  the  latter  certainly  has  considerable  advan- 
tages in  its  favor.  Each  car  is  an  independent  unit,  and 
therefore  no  accident  is  likely  to  cripple  the  entire  system,  as 
might  happen  with  overhead  lines.  The  service,  with  proper 
care,  can  be  made  reasonably  reliable  and  efficient ;  for  heavy 
grade  work  it  is  at  present  out  of  the  question,  but  over  good 
and  level  track  and  under  favorable  conditions  as  regards 
traffic,  storage-battery  traction  even  to-day  has  a  field  for 
usefulness.  So  far  as  we  may  be  permitted  to  learn  from 
experience,  its  cost  does  not  differ  very  widely  from  that  of 
horse-car  service ;  with  everything  favorable  the  advantage 
may  sometimes  lie  on  the  side  of  the  storage  battery ;  under 
other  conditions  it  has  often  been,  and  may  still  continue 
to  be,  in  favor  of  horses.  In  every  case,  with  our  present 


252  THE    ELECTRIC    RAILWAY. 

batteries,  its  cost  is  greater  than  electric  traction  by  the  over- 
head system,  doing  the  same  amount  of  work. 

In  closing,  it  should  be  pointed  out  that  while  in  any  elec- 
tric system  a  carefully  laid  and  substantial  track  is  necessary, 
where  storage  batteries  are  employed  it  is  doubly  so ;  for  not 
only  do  the  irregularities  of  rough  track  and  the  consequent 
jolting  injure  the  accumulators,  but  the  heavy  cars  pound 
the  track  in  a  way  to  cause  serious  deterioration.  The  stor- 
age batteries  of  to-day  are  unfitted  for  heavy  grade  work ; 
their  place  is  on  a  comparatively  level  track.  The  experi- 
ments that  are  now  going  on,  noticeably  at  Washington,  will 
undoubtedly  teach  a  very  useful  lesson  as  to  the  present  state 
of  the  subject.* 

Until  definite  reports  from  them  are  received  one  is  not 
justified  in  counting  too  much  on  the  hopeful  results  of  the 
preliminary  experiments.  An  approximate  statement  from 
the  Dubuque  road  gave  1.5  horse-power  hour  per  car  mile  as 
the  output  required  at  the  station.  This  figure  affords  a 
basis  for  a  rough  comparison  with  the  trolley  system.  The 
average  station  output  in  the  latter  case  is  quite  nearly  i 
horse-power  hour  per  car  mile.  Remembering  that  on  ac- 
count of  the  greater  weight  of  an  accumulator  car  about  a 
third  more  power  is  needed  to  propel  it,  the  relative  effic- 
iencies of  the  two  systems  are  shown  by  the  above  estimates 
to  be  not  far  from  the  figure  deduced  elsewhere. 

Finally,  it  is  only  fair  to  say  that  if  the  accumulator  can  be 
made  durable  or  of  considerably  higher  weight  efficiency  than 
is  now  usual,  it  will  have  a  wide  field  of  operations  wherever 
overhead  wires  are  objectionable.  But,  as  remarked  by  one 
of  the  authors  more  than  two  years  ago  in  discussing  this 
question,  the  time  is  not  yet,  and  it  is  by  no  means  sure  that 
any  of  the  present  types  of  accumulator  will  share  in  the  ul- 
timate success  of  the  system. 

*  A  report  from  the  late  Dubuque  road,  based  on  eight  months'  operation,  gave  the  fol- 
lowing results  :   Cost  of  power  at  station,  including   labor,  coal,  oil,  waste,  repairs,  etc. 
1.80  cents  per  car  mile  ;  batteries,  renewal  expenses  of  every  kind,  3.51  cents  per  car  mile  ; 
ibor  connected  directly  with  the  batteries,  shifting,  cleaning,  etc.,  1.78  cents    per   car 
;  repairs  to  electrical  machinery,  0.13  cent  per  car  mile.      Total  motive  power  ex- 
ises,  7.22  cents  per  car  mile.    These  figures  agree  quite  closely  with  those  already  men- 
l.     A  thorough  investigation  of  the  two  experimental  roads  in  Washington,  D.  C., 
by  a  competent  engineer,  has  shown  the  motive  power  expenses  to  be  not  less  than  ten 
cents  per  car  mile. 


CHAPTER   IX. 

MISCELLANEOUS  METHODS   OF    ELECTRIC   TRACTION. 

TAKING  into  consideration — -as  is  purposed  in  the  present 
chapter — only  electrical  traction  as  it  exists  to-day,  we  must 
recognize  the  fact  that  about  95  per  cent,  of  it  is  accom- 
plished on  the  overhead  system  of  supply  generally  known 
as  the  "trolley"  system,  and  that  the  parallel  method  of  dis- 
tribution is  well-nigh  universally  employed.  Of  the  remaining 
examples  of  electric  roads  a  portion  are  operated  by  the  third 
rail,  or  ordinary  track,  system  of  distribution ;  a  portion  by 
storage  batteries;  a  smaller  portion  by  conduits  of  various 
sorts;  and  the  remainder  is  composed  of  miscellaneous  tel- 
pherage systems  in  a  somewhat  undeveloped  state.  The  so- 
called  series  method  of  distribution  with  constant  currents 
has  been  tried  at  various  times  and  places,  and  has  been, 
with  the  exception  of  one  or  two  small  roads,  abandoned. 
Perhaps  the  most  elaborate  trial  granted  this  plan  was  that 
by  the  Short  Electric  Railway  Company  in  Denver,  Colorado, 
and  to  some  extent  elsewhere.  The  result  of  this  experi- 
ence has  been  a  complete  change  to  the  parallel  distribution 
system. 

There  are  various  good  reasons  for  this.  The  system  of 
switches  and  cross-connections  necessary  in  operating  several 
motors  in  series  on  an  extended  line  has  proved  of  so  for- 
bidding a  character  as  to  deter  further  pursuit  of  the  method. 
Another  reason,  and  one  which  ought  to  have  been  recognized 
from  the  very  start,  is  that  economy  in  conductors  and  effi- 
ciency in  the  motor  system  compels  the  systematic  use  of  the 
highest  voltage  that  can  be  employed  with  entire  safety  to 
life. 

This  is  true  of  whatever  system  of  distribution  is  employed  ; 
and  if  a  given  amount  of  energy  must  be  supplied  for  a  fixed 
line  the  series  system  fails  in  point  of  economy,  if  it  be  lim- 
ited to  a  reasonable  voltage.  Our  present  electric-railway 

253 


254 


THE    ELECTRIC    RAILWAY. 


lines  are  operated  at  a  safe  pressure,  but  one  that  probably 
cannot  be  considerably  increased  without  reaching  the  danger 
limit.  Hence,  wherever  bare  wires  are  to  be  employed,  the 
series  system,  being  limited  to  the  same  total  voltage,  must 
transmit  the  same  current  if  an  equal  amount  of  power  is  to 
be  employed,  and  is  likely  to  lose  both  in  efficiency  of  the 
motors  and  regulating  apparatus,  and  in  the  complications 
before  mentioned^  without  gaining  anything  in  the  line. 

As  regards  the  three-rail  method  of  distribution  referred 
to,  it  was  employed  with  a  fair  degree  of  success  in  some  of 
the  earlier  roads,  but  proved  inconvenient,  owing  to  the 
position  of  the  bare  conductor  with  reference  to  the  earth. 
If  the  third  rail  be  supported  above  the  level  of  the  ground 
on  insulators  it  gets  in  the  way  of  general  traffic ;  if  placed 
on  a  level  with  the  tracks  it  still  menaces,  under  ordinary 
circumstances,  vehicles  and  foot  passengers,  and  becomes 
the  seat  of  insufferable  leakage  at  any  of  the  voltages  now 
generally  used;  hence  it  is  generally  inapplicable.  The 
same  objections  hold  in  case  of  using  the  ordinary  rails  as 
the  conducting  system. 

An  exception  must  be  made,  however,  in  favor  of  lines 
occupying  a  road-bed  peculiarly  their  own,  as  is  the  case  with 
underground  and  elevated  structures,  together  with  such 
surface  roads  as  may  in  rare  cases  be  entirely  isolated  from 
ordinary  traffic. 

Under  these  circumstances  the  third  rail  becomes  a  very 
available  method  of  supply,  and  where  the  current  to  be  dis- 
tributed is  very  considerable,  working  conductors  of  the 
requisite  size  are  perhaps  most  easily  maintained  in  this  way. 
A  noteworthy  example  is  to  be  found  in  the  City  and  South 
London  Railway — that  pioneer  of  high-power  and  high-speed 
electric  traction.  One  or  two  elevated  and  underground 
roads  now  under  contemplation  in  this  country  will  very 
probably  be  operated  in  a  similar  manner. 

The  miscellaneous  systems  of  supply  we  may  conveniently 
divide  as  follows:     (a)  open-conduit  electric  roads;   (b]  closed- 
conduit  electric  roads ;   (c)  telpherage  lines  automatically  con 
trolled  from  one  or  more  points,  and  either  underground  or 
on  trestles  or  aerial  lines. 


MISCELLANEOUS    METHODS    OF   ELECTRIC    TRACTION.      255 

(«)  The  slotted  conduit,  somewhat  similar  to  that  used  on 
cable  roads,  has  been  over  and  over  proposed  and  tried  for 
sheltering  the  conductors — for  the  most  part  with  very  in- 
different success.  The  principal  exponents  of  the  system 
have  been  Bentley  &  Knight  in  this  country  and  Siemens  & 
Halske  in  Germany.  Two  or  three  small  conduit  roads  have 
in  addition  been  operated  in  England,  notably  at  Blackpool 
and  Gravesend,  the  latter  employing,  strange  to  say,  the 
series  system  of  distribution. 

The  Bentley-Knight  roads  in  this  country  have  now  been 
totally  abandoned,  after  long  and  costly  experimenting;  and 
there  is  to-day  no  conduit  road  in  operation  in  America,  un- 
less we  except  an  experimental  one  in  Chicago. 

Abroad,  Siemens  &  Halske  have  met  with  considerable 
success,  particularly  at  Buda-Pesth;  but  how  far  this  result  is 
attributable  to  the  system  employed  and  how  far  to  the  less 
exacting  conditions  of  the  European  climate,  it  is  impossible 
at  present  to  say;  although  the  comparatively  slight  differ- 
ences between  foreign  roads  and  those  abandoned  here  would 
at  least  suggest  that  climate  and  accidents  of  location  have 
much  to  do  with  the  matter. 

The  fundamental  difficulty  with  all  slotted-conduit  electric 
roads  is  the  enormous  difficulty  of  proper  insulation.  This 
arises  from  the  very  nature  of  the  case,  for  the  conductors  are 
placed  in  a  tube  of  limited  diameter  in  free  communication 
with  the  open  air  through  the  slot.  Water,  dirt  and  mud 
inevitably  find  their  way  in,  and  sooner  or  later  the  result 
has  been  either  a  positive  short  circuit  at  a  single  point  or 
general  leakage  along  the  line  in  sufficient  quantity  to  para- 
lyze its  operation. 

A  large  number  of  more  or  less  meritorious  and  ingenious 
forms  of  conduit  have  been  proposed,  varying  in  the  material 
and  arrangement  of  the  various  parts  that  compose  the  sub- 
structure, in  the  position  of  the  conductors  therein,  and  the 
methods  of  insulation  employed.  The  features  possessed  by 
all  in  common  are  the  slot  and  a  pair  of  bare  working  con- 
ductors, placed  in  various  positions  \vith  reference  to  the  slot, 
but  comparatively  close  to  each  other.  Conduits  with  a  single 
working  conductor  and  rail  return  have  been  proposed,  but 


256  THE    ELECTRIC    RAILWAY. 

inasmuch  as  any  connection  between  the  working  conductor 
and  the  conduit  produces  a  severe  short  circuit,  they  have 
not  passed  beyond  the  experimental  stage.  Perhaps  the 
most  elaborate  trial  given  the  conduit  in  this  country  was  in 

the  city  of  Boston,  under  the 
auspices  of  the  Bentley- Knight 
Company.  The  construction 
adopted  is  shown  in  Fig.  107. 
The  road  was  nearly  five  miles 
in  length,  and  was  in  operation 
less  than  one  year,  during  which 
time  the  continual  and  irrepress- 
ible series  of  electrical  misfort- 
unes showed  that  climatic  con- 
ditions forbade  commercial  suc- 
cess. 

The  Siemens  &  Halske  road 
in  Buda-Pesth,Austro-Hungary, 
is  worthy  of  a  little  more  ex- 
tended description,  as  it  is  al- 
most unique  in  its  success. 

The  total  length  of  the  road 
is  now  12.4  miles,  and  50  cars 
are  in  operation.  The  first  sec- 
tion— a  trifle  over  a  mile  and  a 
half  long — was  thrown  open  for 
use  in  July,  1889,  and  the  ex- 
tension has  therefore  been  very  rapid.  The  line  was  built 
at  the  expense  of  the  firm  of  Siemens  &  Halske,  and  may  be 
regarded  as  the  practical  demonstration  of  their  system  on  a 
large  scale. 

The  conduit  is  shown  in  Fig.  108  ;  it  is  placed  directly  under 
one  of  the  rails,  and  in  the  main  is  formed  of  concrete ;  cast- 
iron  yokes  with  flanges  7  inches  wide  are  placed  about  every 
4  feet,  supporting  the  insulators  and  solidifying  the  entire 
construction.  The  oval  conduit  is  1 1  inches  wide  at  the 
widest  point  and  13  inches  deep;  while  the  total  depth  of 
the  conduit  foundations  below  the  top  of  the  rail  is  27^ 
inches.  The  slot  consists  of  a  pair  of  beam  rails,  without 


FIG.   107  -BENTLEY-KXIGHT  CONDUIT 


MISCELLANEOUS    METHODS    OF   ELECTRIC    TRACTION.      257 

any  inside  lower  flange,  secured  to  the  conduit  yokes  by 
wrought-iron  angle  pieces.  The  slot  itself  in  the  finished 
construction  is  an  inch  and  five-sixteenths  wide,  nearly  twice 
as  wide  as  would  be  tolerated  in  this  country.  In  each  yoke 
there  is  a  socket  on  each  side  of  the  conduit  at  its  widest 
point,  and  in  these  sockets  are  carried  the  insulators  to  which 
are  fastened  the  working  conductors.  These  latter  are  made 
of  angle  irons,  and  are  supported  by  the  Y-shaped  projec- 
tions from  the  insulators. 

As  will  be  seen  by  a  glance  at  Fig.  108,  these  are  quite  high 
above  the  floor  of  the  conduit— nearly  a  foot — and,  further- 
more, are  sheltered  by  the  upper  portion  of  the  oval  so  that 
they  cannot  be  readily  touched  from  the  outside,  and  are 
protected  from  the  access  of  rain.  At  convenient  intervals 
there  are  settling  boxes,  connected  with  the  city  sewers;  and 
whatever  water  enters  the  slot  is  collected  at  the  lowest 
points,  and  is  thus  carried  away.  The  distribution  of  power 
is  at  300  volts,  and  the  mains,  instead  of  being  carried  on 


FIG.  108.— SIEMENS  &  HALSKE  CONDUIT— BUDA-PESTH. 

poles,  are  of  lead-covered  cables,  protected  with  iron  bands 
and  laid  in  the  earth  along  the  line.  At  convenient  points 
there  are  junction  boxes,  from  which  feeders  follow  the 
course  of  the  road  and  are  connected  to  the  working  con- 
ductors in  the  conduits. 

The  road  has  grades  up  to  about  i . 5  and  i .6  per  cent.,  and  a 
17 


258  THE    ELECTRIC    RAILWAY. 

considerable  number  of  curves — none  of  them,  however,, 
shorter  than  84  feet  radius.  One  curve  of  148  feet  radius  is 
on  the  steepest  grade. 

The  speeds  permitted  are  from  9,  or  even  12,  miles  per 
hour  in  the  less  densely  populated  portions  of  the  city  to 
barely  4  miles  an  hour  over  street  crossings.  The  daily  car 
mileage  per  car  during  the  16  hours  of  service  is  from  75  to 
90.  The  road  has  certainly  proved  a  commercial  success, 
and  one  of  the  engineers  of  the  company  is  authority  for  the 
statement  that  the  cost  of  running,  exclusive  of  taxes,  is  only 
37  per  cent,  of  the  income.  This  Buda-Pesth  tramway  is 
almost  the  only  conduit  road  in  existence  to-day  of  which  it 
can  be  said  that  its  regular  operation  has  been  a  success. 

As  will  be  seen  from  the  description  just  given,  the  conduit 
itself  possesses  no  very  extraordinary  features ;  it  is  simply 
well  made,  substantial,  and  carefully  drained.  This  latter 
fact  is  probably  the  most  important  factor  in  the  very  good  re- 
sults obtained.  The  concrete  conduit  is  of  itself  a  fair  insula- 
tor, and  serves  to  afford  additional  security  against  grounds. 

A  half-mile  of  conduit  road  is  now  (Dec.  1892)  in  opera- 
tion in  Chicago.  The  conduit  is  of  about  the  dimensions  of 
that  at  Buda-Pesth,  but  is  of  sheet-iron  and  the  conductors 
are  suspended  by  rigid  insulator  blocks  from  above.  The 
general  character  of  the  structure  does  not  insure  immunity 
from  the  difficulties  that  have  caused  the  abandonment  of 
similar  attempts  in  the  past. 

Granting  that  the  difficulties  attending  insulation  could  be 
successfully  surmounted,  the  slotted-conduit  system  in  any/ 
of  the  usual  forms  is  of  doubtful  commercial  value. 

In  the  first  place  it  is  not  generally  applicable,  being  con- 
fined in  its  operations,  by  conditions  not  depending  on  its 
special  excellence,  to  large  cities ;  and,  second,  even  in  these, 
to  locations  where  drainage  is  at  least  reasonably  good.  The 
former  objection  is  true  also  of  the  cable  roads,  which  have 
proved  brilliantly  successful  commercially.  But  difficulty  of  ^ 
drainage,  while  disastrous  to  electric  roads,  is  only  a  slight 
practical  inconvenience  to  the  cable. 

The  most  serious  objection  to  the  underground  electric 
conduit  of  the  open  type  is  its  cost,  the  necessities  of  drainage 


MISCELLANEOUS    METHODS    OF    ELECTRIC    TRACTION.      259 

compelling  the  employment  of  a  tube  of  considerable  dimen- 
sions. The  cost  of  the  substructure  is  high,  $20,000  a  mile 
being  a  moderate  estimate.  Doubtless  many  inventors  of 
such  systems  may  claim  an  expense  vastly  less  than  this,  but 
if  they  guarantee  that  limit,  they  or  their  backers  must  be 
supplied  with  very  well-filled  pocket-books. 

This  high  initial  cost  puts  the  conduit  road  at  a  very  serious 
disadvantage,  compared  with  overhead  roads,  and  perhaps 
•even  with  storage-battery  systems;  for  the  latter,  as  has 
been  already  shown,  can  be  installed  at  an  initial  cost  little 
-exceeding,  in  many  places,  that  of  overhead  systems;  and 
were  the  batteries  to  be  improved  in  even  a  moderate  degree, 
the  interest  charges  and  maintenance  of  the  conduit  and  its 
conductors  would  be  relatively  so  large  as  to  give  the  storage 
battery  the  advantage. 

In  this  connection,  however,  should  be  mentioned  inci- 
dentally a  type  of  slotted-conduit  road  that  has  recently  been 
proposed,  which  obviates  many  of  the  difficulties  of  insula- 
tion, but  unfortunately  substitutes  for  them  others,  which 
will  be  discussed  a  little  later  on  in  connection  with  closed 
conduits.  The  type  of  road  alluded  to  is  one  in  which  the 
working  conductors  are  insulated,  except  for  a  series  of  pro- 
jecting studs  furnishing  current  to  an  arrow  carried  under 
the  car,  by  the  passage  of  which  they  are  thrown  into  con- 
nection with  the  working  conductor  through  a  series  of 
switches.  The  type  is  an  interesting  one,  although  at  pres- 
ent it  is  purely  experimental,  and  on  a  very  small  scale  at 
that. 

(b]  Of  closed-conduit  systems  there  are  many,  elaborated 
by  Pollak,  Lineff,  Gordon  and  others,  abroad,  and  Wheless 
and  others  in  America.  The  violent  opposition  to  the  erec- 
tion of  overhead  wires  in  foreign  countries  has  compelled 
greater  activity  in  this  direction  there  than  in  America. 
These  systems  have  very  much  in  common,  the  fundamental 
idea  of  all  of  them  being  to  put  conductors  permanently 
underground,  and  to  connect  them  automatically — by  the 
passage  of  the  car — to  short  sections  of  working  conductors 
on,  or  immediately  under,  the  surface  and  underneath  the 
car  itself.  By  this  means  the  amount  of  bare  conductor 


260 


THE    ELECTRIC    RAILWAY. 


steadily  subject  to  leakage  or  short  circuits  is  very  much 
reduced.  The  switching-in  of  the  several  sections  is  accom- 
plished generally  by  electro-magnetic  means,  through  current 
supplied  from  the  car. 

These  systems,  in  first  cost,  are  intermediate  between 
overhead  lines  and  the  regular  slotted-conduit  type.  Like 
the  latter,  they  may  be  very  seriously  interfered  with  by  cli- 
matic conditions,  and  are  therefore  somewhat  limited  in 
their  application ;  there  is  also  an  additional  difficulty,  which 
will  be  appreciated  by  every  working  electrician,  due  to  the 
multiplicity  of  switches  intended  to  be  automatic  in  their 
action. 

The  real  seriousness  of  this  difficulty  cannot  be  definitely 
told  until  some  such  road  has  been  in  operation  for  a  consid- 
erable time.  It  will  be  readily  understood,  however,  that  it 
is  by  no  means  negligible,  and  would  probably  be  the  source 
of  a  considerable  amount  of  trouble. 

In  addition  to  these  closed  conduits  or  modified  track 
methods  of  supply  there  exists  a  class  of  conduits  either 


FIG.  109.— VAN  DEPOELE  CONDUIT  WITH  FLEXIBLE  LIPS. 

closed,  but  with  flexible  walls,  or  partially  closed,  having 
only  flexible  lips  to  shut  the  slot,  except  when  the  arrow 
carried  by  the  car  opens  it. 

A  good  example  of  the  latter  construction,  due  to  Mr. 
C.  J.  Van  Depoele,  is  illustrated  here  (Fig.  109).  The 
former  arrangement  is  one  wherein  the  leads  are  inclosed 
in  a  casing  having  flexible  walls.  The  upper  portion  of  this 
casing  is  taken  up  by  the  bare  working  conductor,  and  as 
the  car  passes  along,  carrying  a  trolley  wheel  on  either  side, 
the  pressure  exerted  on  the  working  conductor  is  sufficient 
to  force  it  into  contact  with  the  main. 

These  variations  on  the  conduit  theme  would,  if  mechan- 
ical difficulties  could  be  overcome,  be  very  valuable  adjuncts 


MISCELLANEOUS    METHODS    OF    ELECTRIC    TRACTION.      26l 

to  the  methods  of  distributing  current  now  available.  They 
are,  however,  of  somewhat  dubious  practicability;  for  the 
conditions  to  be  fulfilled  by  a  flexible  insulating  wall  or 
insulating  lips  are  so  severe  as  to  be  almost  forbidding.  Of 
course,  any  of  these  arrangements  can  employ  either  a  con- 
tinuous conductor  or  one  divided  into  sections  automatically 
switched  into  circuit,  as  in  the  Lineff  and  other  systems 
previously  mentioned. 

The  whole  group  of  devices  that  have  just  been  described 
are  interesting  both  mechanically  and  electrically,  but  have 
none  of  them  passed  the  experimental  stage;  and  while  it  is 
perhaps  not  too  much  to  expect  that  something  practical  and 
valuable  will  be  evolved  from  the  amount  of  ingenuity  that 
has  been  spent  upon  them,  the  time  is  not  yet.  This  line 
of  investigation,  however,  is  of  more  than  usual  promise. 

The  number  of  such  modified  conduits  is  too  great  for 
anything  like  elaborate  description.  Figs.  109-113,  how- 
ever, give  a  fair  idea  of  the  Van  Depoele,  Wheless,  Harding, 
Lineff,  and  Pollak-Binswanger  plans,  which  are  fairly  typical 
of  the  directions  in  which  a  successful  solution  of  the  great  dis- 
tribution difficulty  has  been  sought.  We  can  only  suspend 
judgment  on  their  merits  until  they  have  been  proved  by 
experience ;  for  while  the  difficulties  are  evident,  the  prac- 
ticability of  the  means  taken  to  avoid  them  can  only  be  told 
by  protracted  trials. 

The  use  of  alternating  currents  has  now  and  then  been 
proposed  for  electrical  traction,  and  it  is  worth  while  saying 
something,  at  least,  about  their  employment  for  such  pur- 
poses. 

The  alternating  current  has  in  general  two  very  marked 
advantages  over  the  continuous  current  for  all  sorts  of  elec- 
trical distribution  and  service.  The  first  and  most  important 
is  the  great  ease  of  transformation  from  higher  to  lower  volt- 
age and  vice  versa.  This  is  an  immense  convenience,  and  can 
be  made  to  effect  a  very  great  saving  in  the  cost  of  distribu- 
tion; since  it  is  possible  to  distribute  the  electrical  energy 
in  the  form  of  current  of  enormous  voltage  and  then  to  em- 
ploy it  in  the  various  translating  devices  at  as  low  a  voltage 
as  may  be  desirable  for  the  particular  purpose  in  hand. 


262 


THE    ELECTRIC    RAILWAY. 


Inasmuch  as  it  is  difficult  to  insulate  dynamos  and  motors 
for  very  high  voltages,  while  transformers  can  "be  easily 
insulated,  it  becomes  possible  by  their  use  to  accomplish 'the 


FIG.  no.—  WHELESS  CLOSED- CONDUIT  SYSTEM. 


FIG.  in.— HARDING  CLOSED-CONDUIT  SYSTEM. 


o 


o 


FIG.    113.— POLLAK-BlNSWANGER  CLOSED-CONDUIT  SYSTEM. 

distribution  of  the  current  at  any  desired  voltage,  and  to 
utilize  it  at  a  voltage  practicable  for  the  ordinary  translating 
devices. 


MISCELLANEOUS    METHODS    OF   ELECTRIC    TRACTION.       263 

The  second  great  advantage  of  the  alternating  current 
depends  on  its  regulation  in  connection  with  inductive  resist- 
ances wasting  only  a  trifling  amount  of  energy. 

If  there  were  at  present  a  thoroughly  efficient  and  durable 
alternating-current  motor  which  could  be  run  on  the  ordinary 
two-wire  system  of  distribution  and  would  start  readily  under 
heavy  load,  it  would  be  possible  to  employ  alternating  cur- 
rents for  electric-railway  work  with  the  greatest  advantage, 
at  least  upon  long  lines ;  for  a  very  small  amount  of  copper 
would  be  required  for  the  distributing  conductors,  which 
would  feed  the  working  conductor  at  intervals  by  means  of 
transformers.  More  than  this,  the  motors  on  the  cars  might 
be  conveniently  and  economically  regulated  by  a  coil  of  vari- 
able self-induction,  thereby  doing  away  with  one  of  the  diffi- 
culties which  is  at  present  considerable. 

It  must  not  be  forgotten,  however,  that  the  cost  of  trans- 
formers is  not  an  inconsiderable  item ;  so  that  we  should  not 
be  able  to  reap  the  full  advantage  of  the  alternating  current, 
except  in  systems  of  distribution  where  the  cost  of  the  mains 
aside  from  the  working  conductor  is  very  considerable ;  the 
longer  the  line,  the  greater  the  advantage  thus  to  be  obtained. 

Just  at  present,  however,  from  the  lack  of  a  suitable  motor, 
little  headway  is  being  made  toward  alternating-current  rail- 
way systems.  The  "  drehstrom"  motor  has  been  suggested 
for  this  purpose ;  but  the  complications  introduced  by  the 
multiple  leads  required  are  considerable,  probably  so  great, 
wrhen  applied  to  general  traction  purposes,  as  to  overbalance 
the  other  good  features  of  the  machine. 

It  is  not  impossible,  however,  that  some  form  of  alternating- 
current  motor  may  soon  appear  that  will  lend  itself  readily 
to  traction  work ;  and  in  this  case  it  will  be  likely  to  have 
a  considerable  field  in  long-distance  electric  railroading. 

Various  other  suggestions  for  the  use  of  alternating  cur- 
rents have  been  made,  some  of  them  even  going  so  far  as  to 
propose  a  primary  inducing  circuit  in  a  conduit  and  a  secon- 
dary coil  carried  on  the  car.  The  great  difficulty  of  insula- 
tion and  the  lack  of  an  efficient  inductive  relation  between 
the  two  coils  under  such  circumstances  is  enough  to  dis- 
miss the  scheme  without  further  comment. 


264  THE    ELECTRIC    RAILWAY. 

It  will  thus  be  seen  that  there  exist  at  present,  aside  from 
the  regularly  employed  systems  of  electrical  traction,  a  con- 
siderable number  of  arrangements  for  the  distribution  of  cur- 
rent, which  have  not  passed  the  experimental  stage  and  which 
are  possessed  of  more  or  less  merits  and  demerits,  but  no  one 
of  them  is  yet  sufficiently  important  to  entitle  it  to  anything 
more  than  casual  mention  here.  Some  day  one  or  more  of 
these  may  assume  a  position  of  commercial  importance,  but 
until  that  time  comes  we  can  do  nothing  more  than  bring  in 
the  old  Scottish  verdict  of  "  not  proven"  against  their  claims 
of  great  practical  usefulness. 

Passing,  then,  from  these  we  reach  (c]  a  group  of  devices 
for  electrical  traction  that  involve  comparatively  few  new- 
electrical  principles,  but  are  noticeable  on  account  of  certain 
useful  properties  of  their  own.  We  refer  to  the  various  sys- 
tems of  automatically  controlled  electric  roads  intended  in 
the  main  for  freight  and  express  service,  and  designed  to 
simplify  the  conditions  of  traffic  by  permitting  automatic 
control  of  an  electrically  driven  train. 

There  are  two  classes  of  such  devices  that  may  well  be 
separated  from  each  other.  First,  we  may  consider  the  very 
ingenious  systems  of  telpherage  intended  for  the  carrying  of 
freight  at  a  low  cost  and  in  a  very  simple  manner.  Later 
we  shall  have  to  give  some  brief  mention  to  the  plans  for 
high-speed  service  of  a  similar  kind,  intended  to  supplant 
the  pneumatic  tube  and  similar  apparatus  rather  than  merely 
to  serve  as  a  substitute  for  carting. 

Telpherage  owes  its  origin  to  the  late  Prof.  Fleeming  Jen- 
kin,  who  both  devised  the  system  and  coined  its  name.  It 
consists,  in  brief,  of  a  wire-rope  tramway  carrying  suspended 
cars  or  trains  of  cars  driven  by  electric  motors,  to  which 
current  is  supplied  from  the  supporting  rods  or  cables.  Sim- 
ilar apparatus,  driven  by  wire  rope,  is  now  frequently  used — 
principally  for  the  purpose  of  transporting  earth  in  making 
excavations— but  Professor  Jenkin  conceived  the  idea  of  ex- 
tending such  a  service,  and  enabling  goods  and  material  to 
be  transferred  across  country  cheaply  and  rapidly. 

The  appearance  of  a  telpher  line  resembles  that  of  the 
wire-rope  devices  just  mentioned,  consisting  of  a  double  line 


MISCELLANEOUS    METHODS    OF   ELECTRIC    TRACTION.      265 

of  cable  or  rods  suspended  from  stout  posts  and  carrying- 
trains  of  small  cars.  The  general  appearance  of  such  a  line  is 
shown  in  Fig.  1 14,  which  represents  the  system  at  Glynde, 
England,  which  has  been  in  operation  for  several  years,  car- 
rying crude  cement  from  the  pits  out  of  which  it  is  taken  to  a 
railway  siding,  whence  it  can  be  carried  to  the  cement  works. 
The  convenience  of  such  an  arrangement  is  obvious,  al- 
though its  application  may  be  somewhat  limited.  Its  greatest 
merit  is  the  cheapness  of  the  construction  and  the  ease  with 


FIG.  114. -GLYNUE  TELPHER  LINE 

which  it  can  be  operated  where  the  laying  down  of  track 
would  be  inconvenient. 

The  special  feature  in  telpherage  systems  of  this  class  is 
the  method  of  supplying  current  to  the  car.  This  is,  of  course, 
done  through  the  supporting  rods,  but  to  get  contact  with 
both  positive  and  negative  conductors  requires  no  little  inge- 
nuity. 

Of  course,  with  a  pair  of  cables  supporting  each  car,  or 
with  a  cable  and  a  trolley  wire,  the  problem  would  be  very 
straightforward ;  but  in  most  cases — for  cheapness  and  me- 
chanical simplicity — it  has  been  thought  advisable  to  use 
only  a  single  supporting  cable  and  no  subsidiary  conductor ; 
hence  a  little  electrical  complication  is  necessary  to  enable 


266  THE    ELECTRIC    RAILWAY. 

two  cables  to  act  both  as  positive  and  negative  conductors  to 
trains  running  in  both  directions,  one  on  each  cable.  Two 
systems  are  employed  for  this  purpose — the  one,  series  dis- 
tribution at  nearly  constant  current,  such  as  has  been  pro- 
posed for  ordinary  electric  tram-car  lines ;  the  other,  a  very 
ingenious  cross-over  parallel  system,  such  as  is  used  in  the 
Glynde  telpher  line. 

Its  electrical  peculiarities  are  fully  shown  in  Fig.  115.  The 
two  cables  are  divided  into  sections,  electrically  insulated 
from  each  other  as  regards  the  consecutive  sections  of  either 
cable,  but  cross-connected,  so  that  if  any  given  section  of 
either  cable  be  positive  the  next  will  be  negative.  By  using 
two  trolleys  for  the  supply  of  current  to  a  train  somewhat 
longer  than  the  section,  there  will  be  a  steady  flow  of  current 
from  one  section  through  the  motors  to  the  next.  By  this 


X  X  D 


T,i 

FIG.  115.— ELECTRICAL  CONNECTIONS  OF  GLYNDE  TELPHER  LINE. 

device  a  single  pair  of  cables  can  operate  trains  running  in 
both  directions.  A  suspended  electric  locomotive  drags  sev- 
eral cars,  and  is  very  readily  controlled  as  it  approaches  the 
ends  of  the  lines.  In  the  Glynde  line  ten  small  trough- 
shaped  cars  are  used  in  each  train,  and  the  speed  reached  is 
four  or  five  miles  an  hour. 

The  telpher  system  has  never  come  into  any  use  in  this 
country,  but  there  are  at  present  three  lines  operated  in  Eng- 
land, the  longest  being  a  mile  and  a  half.  There  are,  of 
course,  a  considerable  number  of  ingenious  minor  devices  for 
the  securing  of  constant  speed  and  the  proper  control  of  trains, 
and  besides,  an  automatic  block  system  is  provided,  so  that 
there  will  be  no  danger  of  rear-end  collisions. 

Satisfactory  work  can  be  done  in  this  line  of  automatic 
transportation  of  goods,  and  it  would  not  be  surprising  to 
see  it  come  into  occasional  very  efficient  use  in  localities 
where  ordinary  tramways  are,  from  considerations  of  cost  or 


MISCELLANEOUS    METHODS    OF    ELECTRIC   TRACTION.      267 

difficult  country,  impracticable.  The  supporting  structure 
can  be  made  comparatively  light ;  the  cables  or  rods  need  be 
less  than  an  inch  in  diameter,  and  a  large  amount  of  goods 
can  be  carried  at  a  comparatively  small  cost.  Such  lines 
are  perhaps  at  their  best  in  serving  as  feeders  to  railway 
lines,  connecting  them  with  manufactories,  mines,  quarries, 
and  the  like. 

In  America,  however,  the  system  has  not  yet  been  intro- 
duced practically,  although  small  experimental  roads  have 
been  operated  in  years  past  by  Mr.  Daft  and  Mr.  Van  Depoele. 
Nothing  commercial  has  come  from  these  experiments,,  and 
just  at  present  there  is  no  sign  of  further  development. 

The  motors  and  electrical  arrangements  generally  of  tel- 
pher lines  present  no  specially  striking  features,  the  only 
apparatus  in  any  way  peculiar  being  safety  and  controlling 
devices,  which  may  be  arranged  in  a  large  number  of  ways, 
according  to  the  fancy  of  the  individual  inventor  who  has 
the  problem  in  hand. 

Owing  to  the  beautiful  manner  in  which  electrically  oper- 
ated vehicles  can  be  controlled  from  any  given  point,  the 
idea  of  an  automatic  electric  railway,  with  great  capabilities 
for  speed  and  of  a  simple  and  cheap  construction,  has  proved 
peculiarly  attractive  to  the  minds  of  inventors. 

The  telpher  system  of  which  we  have  just  spoken,  is  the 
mere  rudiment  of  automatic  electric  traction,  and  develop- 
ment in  the  direction  of  higher  speed  and  greater  permanence 
of  service  was  very  natural.  It  would  seem  at  first  sight  to 
be  quite  within  the  bounds  of  possibility  to  lay  a  narrow- 
gauge  track  upon  a  comparatively  cheap  elevated  structure, 
and  to  run  upon  it  trains  suitable  for  the  transportation  of 
mail  and  express  matter;  substitute  rails  and  permanent 
structures  for  the  cables  or  rods  of  the  telpher  line,  increase 
the  speed,  and  the  problem  would  appear  to  be  solved. 

The  possibility  of  running  an  electric  train  in  some  such 
fashion  at  the  rate  of  100  or  150  miles  an  hour  has  been 
recognized  by  many  of  those  connected  with  the  development 
of  electric  traction.  There  are,  however,  a  few  electrical 
difficulties,  more  mechanical  ones,  and  commercial  consider- 
ations of  a  most  forbidding  character. 


268  THE    ELECTRIC    RAILWAY 

The  telpher  line  carrying  its  burden  of  ore  or  luggage  of 
various  sorts  over  a  comparatively  short  distance  is  relatively 
practical;  but  where  a  train  is  to  be  run  at  a  speed  of  100 
miles  an  hour  over  a  distance  of  100  miles,  more  or  less, 
peculiar  conditions  are  encountered.  In  particular,  such 
high-speed  service  is  only  desirable  for  the  transportation  of 
things  comparatively  small  in  bulk  and  comparatively  great 
in  value,  therefore  the  class  of  goods  which  the  owners 
would  least  care  to  trust  to  an  automatic  service,  where  acci- 
dents would  be  especially  serious  in  their  results. 

It  is  very  doubtful,  indeed,  whether  the  United  States  Gov- 
ernment would  ever  consent  to  intrust  its  mails  between 
New  York  and  Boston,  for  e'xample,  to  any  automatic  system 
whatever,  on  account  of  the  great  ease  with  which  it  could 
be  interfered  with  and  the  mails  robbed,  and  the  serious 
delays  that  even  a  trifling  accident  could  produce. 

As  soon  as  such  a  service  ceases  to  be  automatic  it  loses 
much  of  its  distinctive  character,  and  might  as  well  be  ex- 
tended into  a  general  high-speed  electric  road  intended  for 
transporting  passengers  as  well  as  express  matter.  Such  a 
development  is  highly  desirable  and  quite  practicable,  but 
an  electrical  high-speed  package  express  running  unguarded 
and  unwatched  over  long  distances  is  well  subject  to  the 
ancient  criticism  of  being  "  neither  fish,  flesh,  nor  good  red 
herring." 

Nevertheless,  just  such  schemes  have  been  brought  forward 
over  and  over  again ;  and  one  of  them — the  Weems  project — 
is  described  in  Chapter  X.  in  considerable  detail,  and  has 
proved  of  great  value  to  the  cause  of  electric  traction  by 
demonstrating  on  a  small  scale,  but  none  the  less  effectively, 
the  possibility  of  enormous  speeds. 

The  logical  line  of  development  from  the  experiments  is 
the  electric  lightning  express,  as  sketched  in  the  same  chapter. 
Very  high  speeds  require  remarkably  well-constructed  track 
and  road-bed,  and  this  is  really  one  of  the  most  serious  diffi- 
culties that  has  to  be  encountered.  A  road-bed  and  line 
equipment  of  suitable  character  is  expensive  in  a  prohibitive 
degree,  unless  the  traffic  is  to  be  heavy  and  will  pay  unusu- 
ally well. 


MISCELLANEOUS    METHODS    OF    ELECTRIC    TRACTION.      269 

Furthermore,  the  line  must  be  of  considerable  length  in 
order  to  render  high  speed  worth  attaining.  At  the  rate  of 
100  miles  per  hour,  getting  up  speed  and  stopping  requires  so 
much  space  and  power  that  the  advantages  of  so  great  a  speed 
are  almost  thrown  away  unless  the  road  extends  over  a  con- 
siderable distance. 

All  these  considerations  point  to  the  true  electric  railway 
rather  than  to  any  automatic  system.  Nevertheless,  several 
of  the  latter  have  been  proposed.  For  the  most  part  they 
embody  no  striking  features,  save  a  number  of  ingenious 
devices  for  the  proper  governing  of  speed,  automatic  slowing 
down  and  stopping,  and  the  regulation  of  the  train  from  a 
distant  point.  These  only  possess  interest  in  so  far  as  they 
have  been  carried  out,  and  they  have  not  been  carried  out 
except  in  the  Weems  road  before  mentioned  and  in  one  other, 
of  which  we  will  now  speak. 

The  only  automatic  high-speed  road  which  is  in  even  ex- 
perimental operation  to-day  is  that  strange  freak  of  an  in- 
ventor's ingenuity — the  Portelectric  system.  Abandoning 
all  idea  of  driving  wheels  with  their  motor  and  motor  arma- 
ture, the  inventor  of  this  scheme  has  proposed  to  utilize 
the  direct  attraction  of  solenoids  for  a  hollow  steel  car 
running  on  a  suitable  track.  There  are  required  a  con- 
tinuous series  of  solenoids  over  the  entire  length  of  the 
line,  each  of  them  powerful  enough  to  exert  a  strong  attract- 
ive pull  on  the  car  and  furnished  with  current  at  the  proper 
time  by  automatic  switches  opened  and  closed  by  the  passage 
of  the  flying  armature,  a  plan  suggested  long  ago  abroad.* 

Working  models  were  constructed,  and,  of  course,  worked 
well,  as  model  systems  always  do;  and,  encouraged  by  this, 
still  further  experiments  were  made,  and  there  has  been 
until  recently  near  Boston  an  oval  experimental  track  about 
half  a  mile  long.  It  consisted  of  an  upper  and  lower  rail, 
the  car  being  provided  with  flanged  wheels  above  and  below. 
The  car  itself  was  a  wrought-iron  elongated  shell  with  ogival 
ends,  12  feet  long,  and  weighing  500  pounds.  The  solenoids 
were  placed  six  feet  apart,  and  each  was  composed  of  20 

*  See  English  patent  No.  58,  of  1862. 


270 


THE    ELECTRIC    RAILWAY. 


pounds  of  No.  14  copper  wire,  having  a  resistance  of  about 
5  ohms ;  the  successive  solenoids  were  thrown  into  circuit  in 
front  of  the  car  by  the  action  of  a  contact  wheel  mounted 
upon  the  latter  and  running  upon  the  upper  rail,  which  was. 
divided  into  sections  and  utilized  as  a  conductor. 

It  was  expected  that  enormous  speeds  would  be  reached ; 
this  belief,  however,  has  not  been  justified,  as  nothing  even 
roughly  approximating  the  speed  obtained  by  one  of  the 
authors  in  an  experimental  run  on  the  Weems  system  has 
ever  been  reached.  The  efficiency  of  such  apparatus  is  ob- 
viously, from  the  character  of  the  electro-magnetic  action 
involved,  low ;  and  the  sparking  from  the  inductive  currents 
set  up  in  the  helices  as  the  contact  is  broken  has  proved  to- 
be  most  severe,  although  this  might  be  partially  obviated  by 
short-circuiting  the  helices  instead  of  cutting  them  out. 

An  idea  of  the  actual  efficiency  of  the  apparatus  may  be 
obtained  by  considering  the  fact  that  between  9  and  10  elec- 
trical horse-power  were  required  to  drive  the  car  at  a  speed 
of  33 YZ  miles  per  hour — 50. feet  per  second.  Portions  of  the 
track  were  level,  and  in  other  portions  there  were  grades  of 
small  length,  but  rising  as  high  as  4  per  cent.  The  total 
weight  of  the  car  being  500  pounds,  assuming  any  reasonably 
plausible  traction  co-efficient,  it  is  evident  that  the  efficiency 
obtained  was  quite  low.  This  much  space  is  devoted  to  the 
discussion  of  this  very  unusual  system  simply  by  reason  of 
its  striking  peculiarities,  and  not  from  any -probability  that 
such  a  device  can  ever  supplant  the  electric  motor'  proper ; 
unless,  possibly,  on  a  small  scale,  as  a  substitute  for  the 
pneumatic  tube. 

As  it  is,  the  present  chapter  has  been  necessarily  some- 
what disjointed  in  character,  having  dealt  with  a  wide  range 
of  subjects — treating  schemes  practical  and  impractical,  pos- 
sible and  abandoned  as  hopeless. 

To  the  minds  of  the  authors  the  most  hopeful  of  the 
methods  mentioned  are  some  of  the  modified  conduits. 
There  are  no  signs  as  yet  that  any  of  these  deserves  more 
extended  mention  than  we  have  accorded  to  it  here.  Never- 
theless, their  development  should  be  very  carefully  watched ; 
for  the  direction  is  one  from  which  something  important 


MISCELLANEOUS    METHODS   OF   ELECTRIC    TRACTION.      27 1 

may  be  looked  for,  and  from  which  something  practical  may 
be  reasonably  hoped. 

The  slotted  conduit,  although  it  has  been  shown  from 
experience  that  it  may  be  successful,  is  both  commercially 
and  electrically  somewhat  discouraging  in  our  American  cli- 
mate; possibly  its  very  best  chance  for  giving  good  results 
is  in  the  conversion  of  some  of  the  existing  cable  roads  into 
electric  roads.  With  conduits  so  large  as  those  employed 
for  cables  the  difficulties  of  drainage  would  be  reduced  to  a 
minimum,  insulation  would  probably  be  practicable,  and,  at 
least  on  roads  of  considerable  length,  as  good  efficiency  could 
be  obtained  as  with  cables.  With  respect  to  any  and  all  of 
the  other  devices,  we  can  only  advise  our  readers  to  suspend 
judgment  awaiting  further  evidence. 


CHAPTER  X. 

HIGH-SPEED    SERVICE. 

UNDER  this  heading  it  is  intended  to  consider  such  service 
as  involves  greater  speeds,  distances,  and,  usually,  greater 
loads  than  occur  in  street-railway  work,  properly  so  called. 

To-day  there  is  little  to  record  of  actual  accomplishment 
in  this  direction.  The  City  and  South  London  Railway 
stands  as  a  unique  example  of  rapid  transit  for  large  cities, 
in  which  several  cars  are  run  in  a  train,  on  a  special  roadway, 
permitting  higher  than  any  allowable  street  speeds. 

In  1886  Mr.  F.  J.  Sprague  conducted  experiments  on  the 
New  York  Elevated  Railway,  having  in  view  the  replacement 
of  the  steam  locomotives  in  a  service  requiring  five  loaded  cars, 
each  about  35  feet  long,  to  be  hauled  at  a  maximum  speed  of 
30  miles  per  hour.  Mr.  Leo  Daft,  during  the  years  1888  and 
1889,  made  similar  experiments.  The  failure  to  attain  im- 
mediate success  may  be  traced  in  both  cases  to  several  causes 
— immaturity  of  motor  design  at  that  time,  limitation  of 
money  available  for  making  needed  changes,  difficulty  of 
experimenting  without  disturbance  of  regular  traffic,  and  occu- 
pation of  the  experimenters  in  other  absorbing  work. 

In  the  light  of  the  experience  of  to-day  no  one  of  the 
competent  engineers  who  has  had  to  do  with  the  electric-rail- 
way work  of  the  last  few  years  would  hesitate,  if  supplied 
with  the  proper  amount  of  money,  to  undertake  the  success- 
ful installation  of  an  electric  rapid  transit  system  meeting 
all  the  requirements  of  the  New  York  elevated  railway  or 
London  underground  service.  The  conditions  are  in  many 
respects  much  simpler  than  those  met  with  on  the  streets. 
Especially  is  this  true  in  regard  to  the  placing  of  the  con- 
ductor system  in  the  common  street,  where  the  convenience 
of  the  electrical  engineer  must  be  subordinated  to  every 
immemorial  right  of  man,  beast,  or  tree. 


HIGH-SPEED    SERVICE. 


2/3 


And  the  motors  may  be  placed  where  dust  and  mud  do  not 
corrupt  and  stones  do  not  break  in  the  fields. 

A  brief  description  of  the  City  and  South  London  plant 
will  illustrate  the  comparative  simplicity  of  this  class  of  work. 
The  propelling  power  for  each  locomotive  comes  from  two 
motors,  the  armatures  of  which  are  concentric  with  the  axles 
and  keyed  directly  thereto.  Each  armature  is  rated  at  about 
50  horse-power,  at  a  normal  speed  of  25  miles  per  hour.  The 
motor  frames  are  inclined  upward  as  shown  in  Fig.  1 16.  For 
the  outgoing  side  of  the  circuit  the  working  conductor, 
divided  into  convenient  sections,  is  of  channel  steel.  Cur- 
rent is  taken  from  this  through  a  sliding  contact  shoe  attached 


CONDUCTOR  RAIL  LEVEL 

FIG.  n6. -ELECTRIC  LOCOMOTIVE  OF  CITY  AND  SOUTH  LONDON  RAILWAY. 

to  the  locomotive.  For  the  other  side,  the  rails  are  used  as 
in  ordinary  practice.  The  channel  steel  is  insulated  from 
the  road-bed  by  glass  insulators,  the  general  line  pressure 
being  500  volts.  The  motors  are  series  wound  and  regula- 
tion is  effected  through  a  rheostat  placed  in  the  main  circuit. 

We  have  been  able  to  obtain  but  little  information  con- 
cerning the  actual  operating  expenses  of  this  line.  Reports 
indicate  that  they  have  at  least  been  satisfactory  to  the  bond- 
holders. 

The  subject  of  the  relative  economy  of  steam  and  electric 
train  service  was  discussed  by  one  of  the  authors  in  a 
paper  read  before  the  American  Institute  of  Electrical  En- 
18 


274  THE    ELECTRIC    RAILWAY. 

gineers  in  May,  1890.  As  the  matter  was  then  taken  up 
quite  in  detail,  and  as  no  later  developments  have  been  found 
to  alter  the  conclusions  then  reached,  we  draw  largely  upon 
that  paper  for  this  chapter. 

As  will  be  seen,  the  question  in  regard  to  electricity  is  not 
"Can  it  be  done?"  but  "Can  it  be  done  more  economically 
than  by  steam?" 

In  the  light  of  present  achievements  we  may  state  without 
argument  the  following  propositions : 

First — It  is  possible  to  construct  motors  capable  of  doing- 
the  maximum  work  required  to-day  in  transportation. 

Second — It  is  possible  continuously  to  generate  electrical 
energy  equal  to  the  capacity  of  any  number  of  such  motors. 

Third — At  any  desired  loss  and  over  any  desired  distance 
it  is  possible  to  supply  by  the  running-contact  method  the 
necessary  current,  at  considerable  pressure,  for  the  working 
of  such  motors. 

Should  there  still  be  question  in  the  mind  of  any  as  to 
the  value  of  the  running-contact  method  at  speeds  much 
higher  than  those  commonly  used,  it  may  be  stated  that  75 
amperes  at  500  volts  have  been  thus  continuously  supplied 
to  a  car  moving  at  more  than  1 10  miles  an  hour.* 

These  premises  being  established,  further  discussion  di- 
vides itself  into  three  parts: 

First,  As  to  the  mere  possibility,  without  reference  to  the 
economy,  of  steam  and  electric  propulsion  under  given  con- 
ditions. 

Second,  As  to  the  relative  cost  of  exerting  in  a  locomotive 
any  unit  of  power  by  electric,  as  compared  with  direct  steam, 
motors. 

TJiird,  As  to  the  relative  amount  of  power  required  by  the 
two  agents  to  transport  a  given  paying  load  under  given 
conditions. 

In  using  the  word  steam  as  above  we  have  in  mind  only 
the  direct  application  of  steam  power  on  the  tnx-ks.  The 
case  of  cable  propulsion  is  not  here  compared,  as  that  has 

*  See  "Report  of  High-Speed  Electric  Railway  Work,"  read  Feb.  24,  1891,  before  the 
American  Institute  of  Electrical  Engineers  by  O.  T.  Crosby. 


HIGH-SPEED    SERVICE.  3/5 

within  its  restricted  field  of  application  already  often  been 
compared  with  horse,  steam,  and  electric  power. 

The  limiting  possibilities  of  locomotion  may  be  understood 
by  considering  a  prolongation  of  the  lines  of  present  practice 
in  the  direction,  first,  of  loads  handled;  second,  grades 
climbed;  third,  speeds  attained;  and,  fourth,  length  of  con- 
tinuous runs. 

Since  the  effect  of  grade  as  compared  with  load  is  simply 
to  increase  the  tractive  effort  required  for  a  given  load  and 
speed,  it  need  not  be  separately  treated,  except  that  there 
has  been  some  question  of  increase  of  adhesion  in  the  ground- 
return  method,  which  in  extreme  cases  might  appear  as  an 
advantage  for  electric  propulsion.  The  matter  is  not  of 
great  importance;  and  we  will  refer  to  it  only  so  far  as  to 
say  that  general  experience  and  some  special  tests  show 
that  the  adhesion  co-efficient  is  not  increased  in  any  practi- 
cal degree  by  the  mere  passage  of  the  current  from  wheel 
to  rail. 

The  capacity  of  an  electric  engine,  like  that  of  a  steam 
engine,  to  haul  any  given  load  is  measured  by  the  tractive 
effort  possible  to  be  produced  and  the  relation  between 
weight  and  adhesion  for  given  track  conditions.  The  ready 
multiplication  of  cylinders  in  the  one  case  and  armatures  in 
the  other,  while  maintaining  mechanical  unity  and  the  ready 
coupling  of  distinct  locomotive  units,  renders  the  whole  ques- 
tion of  capacity  to  exert  a  given  horizontal  effort,  without 
regard  to  the  time  element,  unimportant.  It  goes  without 
saying  that,  if  desired,  a  single  armature  may  be  constructed 
capable  of  exerting  as  great  a  drawbar  strain  as  any  locomo- 
tive now  in  use. 

As  to  limiting  speeds,  it  is  not  easy  to-day  to  make  even 
"  an  educated  guess,"  either  for  steam  or  electric  propulsion. 
The  high  figures  for  steam  that  have  been  recently  presented 
both  from  England  and  America  are  higher  than  the  limiting 
figures  as  they  would  have  been  given  by  many  competent 
authorities  only  a  few  years  ago.  Eighty-six  miles  per  hour 
in  England,  on  the  Northeastern  Railway,  eighty-seven  miles 
per  hour,  and  later  a  rate  of  90.45  miles  per  hour,  in  this 
country,  on  the  Reading  iRailway,  have  been  reported  since 


2-5  THE    ELECTRIC    RAILWAY. 

Jan.  i,  1890.  These  runs  a-re  noteworthy  not  only  for 
the  fact  of  unusual  speed,  but  because,  as  shown  by  indicator 
cards  in  the  English  case,  and  as  may  be  deduced  from  the 
consideration  of  the  maximum  cylinder  power  in  the  Ameri- 
can case,  the  train  resistances  are  far  below  the  values  that 
would  have  been  predicted  by  even  the  most  liberal  of  the 
received  formulae  on  the  subject.  The  total  resistance  per 
ton,  as  per  indicator  card,  in  the  86-mile  run  was  only  13.4 
pounds.  According  to  Searles'  formula,  adopted  by  Well- 
ington, it  should  be  69  pounds,  engine  and  tender  being 
taken  at  50  tons.  The  load  of  347  tons  was  carried  at  86 
miles  per  hour  by  an  expenditure  of  1,068  horse-power — this 
on  a  level.  The  engine  was  compound. 

Would  it  be  possible  to  attain  a  speed  twice  as  great,  or 
say  150  miles  per  hour? 

A  driver  24  feet  in  circumference  must  revolve  550  times 
per  minute  in  order  to  travel  13,200  feet  per  minute,  or  150 
miles  per  hour — this  without  slip.  Since  in  the  case  consid- 
ered the  revolutions  per  minute  reached  309,  and  since  in 
the  Reading  case  a  much  higher  rate  must  have  been  reached 
— the  drivers  being  smaller — and  since  on  stationary  engines 
a  speed  much  above  550  revolutions  per  minute  has  been 
attained,  it  seems  beyond  question  that  from  this  point  of 
view  the  supposed  case  is  quite  possible. 

Considering  the  matter  of  steam  supply,  we  are  again 
brought  to  consider  the  whole  question  of  train  resistances 
at  all  speeds. 

Total  resistance  to  motion  should  'be  sharply  divided  into 
two  classes:  the  resistance  due  to  motion  through  air,  and 
that  due  to  friction  and  blows  between  vehicle  and  track  and 
to  friction  and  blows  between  parts  of  the  vehicle. 

For  the  most  part,  those  who  constructed  the  formulas 
now  found  in  the  text-books  worked  on  road-beds  far  infe- 
rior to  the  best  work  of  to-day,  at  speeds  much  less  than 
those  now  attained,  and  with  wrong  values  for  at  least  one 
of  the  species  of  resistance — the  atmospheric.  On  this  point 
there  has  recently  been  presented,  as  the  result  of  experi- 
ments at  high  velocities,  a  formula  showing  the  pressure  to 
be  approximately  a  function  of  the  first,  instead  of  the  second, 


HIGH-SPEED    SERVICE.  2// 

power  of  the  velocity  as  ordinarily  assumed.*  A  convenient 
datum  point  may  be  given,  stating  that  at  100  miles  per  hour 
the  pressure  on  one  square  foot,  normal  to  the  direction  of 
motion,  is  13  pounds;  while  proper  shaping  of  the  front  may 
reduce  this  to  6.5  pounds.  The  absolute  values  given,  while 
corresponding  quite  closely  with  those  of  received  formulae 
in  the  neighborhood  of  the  velocities  heretofore  experimen- 
tally attained,  depart  widely  from  those  assumed  for  velocities 
higher  than  30  miles  per  hour,  and  calculated  by  the  quad- 
ratic relation  between  velocity  and  pressure.  Using  the 
more  trustworthy  values,  we  are  able  to  separate  more  nearly 
than  heretofore  has  been  possible  the  atmospheric  from  all 
other  resistances  met  at  high  velocities.  Some  inaccuracy 
still  remains,  by  reason  of  the  difficulty  of  obtaining  exact 
measure  of  the  resisting  areas  in  a  train ;  but  by  study  of 
careful  tests  made  by  others  on  the  New  York  Central  and 
on  English  roads  we  find  that  over  the  range  from  about  40 
up  to  80  miles  per  hour  the  tonnage  co-efficient  seems  prac- 
tically constant  at  8  pounds.  This,  of  course,  applies  only  to 
first-class  road-bed  and  rolling  stock.  Whether  this  co-effi- 
cient remains  constant  at  higher  speeds  we  do  not  know. 
There  is  no  reason  to  assume,  as  has  often  been  done,  that  it 
increases  with  the  square  of  the  velocity;  and,  on  the  other 
hand,  it  will  not  be  safe  to  assume  constancy.  From  experi- 
ments made  with  a  single  2. 5 -tons  car  at  about  100  miles  per 
hour,  the  tonnage  resistance  at  that  speed  seems  to  be  about 
20  pounds  per  ton.f  Though  this  value  seems  quite  high  as 
compared  with  the  eight  pounds  at  80  miles  per  hour,  the 
difference  is  in  large  part  to  be  explained  by  the  poor  condi- 
tion of  the  track  used  for  the  experiment  and  a  constant 
curvature  which  would  call  for  about  four  pounds  per  ton. 
Until  better  evidence  can  be  had  it  will  *be  safe,  at  least,  to 
assume  a  value  of  20  pounds  per  ton,  on  a  first-class  track, 
with  good  rolling  stock,  at  125-150  miles  per  hour. 

Having  made  this  necessary  digression,  we  may  return  to 
the  matter  of  steam  supply,  and  state  that  by  reducing  weight 

*  "An  Experimental  Study  of  Atmospheric  Resistance,"  by  O.  T.  Crosby,  London 
Engineering,  May  30,  June  6-13,  1890;  New  York  Engineering  Neivs,  May  31,  June  7-14,  1890, 
and  The  Electrical  World.  May  24,  1890. 

t  "Report  of  High-Speed  Railway  Work"  above  mentioned. 


278 


THE   ELECTRIC    RAILWAY, 


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HIGH-SPEED    SERVICE. 


279 


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28o  THE    ELECTRIC    RAILWAY. 

and  area  both  to  something  less  than  one-half  the  existing 
values  in  the  86-mile  run,  the  same  effort  would  produce  the 
speed  150  instead  of  86.  The  area  cannot  be  thus  reduced, 
but  by  assuming  a  greater  reduction  in  weight — say  to  100 
tons,  or  to  little  more  than  engine  and  tender — maintenance 
of  the  higher  speed  might  become  possible,  with  nearly  the 
same  steam  expenditure  as  in  the  recorded  case. 
.  To  attain  that  speed,  from  rest,  might  require  such  orig- 
inal weight  of  fuel  and  such  length  of  favorable  track  as  to 
make  the  feat  practically  impossible  with  steam.  This  leads 
us  to  inquire  into  the  dead  weight  necessary  for  hauling,  say, 
one  ton  at  different  speeds.  Table  I.  gives  the  horse-power 
required  for  exerting  the  tractive  effort  for  one  ton  at  various 
speeds,  at  various  efficiencies,  with  various  values  of  cross- 
section  per  ton,  and  with  the  two  agents — steam  and  elec- 
tricity. 

Column  i  shows  speed  in  miles  per  hour  from  20  to  140; 
column  2,  corresponding  tonnage  co-efficient,  or  resistance, 
in  pounds  per  ton,  exclusive  of  atmospheric  resistance.  Col- 
umns 3  to  8,  inclusive,  show  horizontal  effort  needed  for 
overcoming  atmospheric  resistance  under  various  assumptions 
as  to  area  exposed  per  ton,  from  i  square  foot  to  o.  i  square 
foot  per  ton.  The  former  figure  corresponds  nearly  to  the 
case  of  a  heavy  locomotive  propelling  itself  alone.  As  load 
is  put  on  behind  it  other  ratios  are  formed.  Oblique  surfaces 
are  supposed  to  be  reduced  to  equivalent  normal  surfaces. 
Columns  9  to  14,  inclusive,  show  rate  of  work  in  horse-power 
per  ton  for  the  various  cases  of  area  exposed  to  atmospheric 
resistance,  efficiency  of  locomotive  being  taken  at  90  per 
cent.  Columns  15  to  17,  inclusive,  show  horse-power  per 
ton  for  the  extreme  and  middle  cases  of  exposed  area,  and 
for  locomotive  efficiency  of  80  per  cent.  Columns  18  to  20, 
inclusive,  show  same  for  efficiency  of  60  per  cent.  Columns 
21  to  26,  inclusive,  show  weight  of  coal  and  water  per  ton 
carried  for  one  hour,  assuming  5  pounds  of  coal  and  25  pounds 
of  water  per  horse-power  hour  on  a  steam  locomotive.  The 
coal  figure  is  very  close  to  actual  practice.  The  water  figure 
is  less,  but  makes  allowance  for  scooping  water  at  convenient 
intervals.  Continuous  scooping  is  not  considered  practical 


HIGH-SPEED    SERVICE.  28 1 

or  economical.  Columns  27  to  29,  inclusive,  show  weight  of 
steam  locomotive  and  tender  required  to  generate  the  required 
horse-power  per  ton,  under  the  assumption  of  100  pounds 
per  horse-power  and  90  per  cent,  efficiency.  Only  three 
cases  of  exposed  area  are  taken ;  that  is,  one  foot,  one-half  a 
foot,  and  one-tenth  of  a  foot  per  ton.  The  weight  of  steam 
locomotives  is  not  calculated  for  any  other  efficiency  figure 
than  90  per  cent.,  as  this  seems  to  be  quite  constantly  attained 
or  surpassed.  The  assumption  of  100  pounds  per  horse-power 
is  closely  true  for  many  good  types  of  locomotive  when 
working  at  speeds  from  60  to  80  miles.  At  lower  speeds  this 
figure  is  too  low,  but  it  is  assumed  that  for  any  ruling  speed 
engines  may  be  built  of  minimum  weight  for  that  speed.  In 
passing  through  lower  than  ruling  speeds  both  electric  and 
steam  motors  work  at  low  output  per  pound  of  weight;  hence 
the  assumption  of  constant  weight  per  horse-power  will  not 
introduce  error  materially  affecting  comparative  results.  At 
higher  speeds  than  80  miles  existing  engines  would  show 
less  than  100  pounds  per  horse-power;  but  as  their  boiler 
capacity  is  reached  at  that  speed  the  necessary  increase  for 
any  regular  wrork  would  carry  the  weight  figure  to  very  nearly 
the  figure  given  for  the  60  to  80  mile  running.  Columns  30 
to  32  show  weight  of  steam  locomotive  and  tender,  plus  weight 
of  fuel  and  water,  per  ton  hauled ;  also  weight  of  load — freight 
and  freight  car — that  may  be  hauled  by  such  weight  of  motive 
power;  the  load  figures  being  obtained  by  subtracting  the 
motive  power  weights  from  2,000  pounds.  Columns  33  to 
41  show  corresponding  figures  for  electric  locomotives,  under 
the  assumption  of  60  pounds  per  horse-power,  and  at  the 
three  efficiencies — 90,  80,  and  60  per  cent.  In  30  to  41, 
inclusive,  weight  of  load  is  written  first,  wreight  of  locomotive 
(plus  tender,  fuel,  and  water  for  steam)  being  written  below. 
The  60  pounds  per  horse-power  covers  weight  of  the  con- 
taining car  for  motors.  We  cannot  here  go  into  detailed 
figures  on  this  point,  but  believe  that  any  investigation  will 
find  the  figure  safe,  supposing  always  that  the  unit  be,  say,  25 
horse-power  or  more.  Columns  42  to  53,  inclusive,  show 
the  horse-power  required  to  be  exerted  for  hauling  one  ton 
of  load,  i.e.,  freight  and  freight  car,  the  relation  between 


282 


THE    ELECTRIC    RAILWAY. 


these  two  being  taken  as  the  same  for  either  steam  or  electric 
propulsion,  hence  not  necessary  to  enter  here.  These  col- 
umns apply  to  steam  at  90  per  cent,  and  to  electricity  at  90, 
So,  and  60  per  cent.,  and  for  the  three  cases  of  exposed  area. 
They  are  readily  obtained  from  the  previous  columns  by 
making  allowance  for  the  horse-power  necessary  to  haul  that 
part  of  every  ton,  total  weight,  which  must  go  into  motive 
power,  machinery,  and  fuel.  Columns  54  to  62,  inclusive, 
show  the  ratios  between  horse-power  required  by  the  two 
agents  for  hauling  a  ton  of  load  (freight  and  freight  car)  at 
the  different  speeds,  efficiencies  and  area  relations. 

It  is  plain  that  if  we  can  now  obtain  the  ratio  of  cost  per 
horse-power,  as  given  by  the  two  agents,  in  the  corresponding 
cases,  we  can  easily  determine  the  speeds  at  which  the  one 
or  the  other  agent  becomes  the  more  economical. 

Let  us  first  obtain  the  cost  of  electric  propulsion. 


TABLE    II. 

COST  OF  ONE  H.    P.   HOl' 


ELECTRIC,  IN  CENTS. 


800 

. 

5' 

Engineer  0.4 
Fireman  0.3 
Dvnamo  man  0.4 
Helper   .                                    02- 

0.13 
o.  10 
0.13 

0.08 
0.06 

0.037 

0.04 
0.03 
0.04 

0.04 

0.03 
0.04 

0.04 
0.03 

0.04 

0.03 
0.04 

0.04 

0.03 
0.04 

0.04 
0.03 

0.04 

0.04 
0.03 

0.04 

Superintendence  [0.30 

O.IO 

0.06 

0.037 

o.o3J 

0.02 

0.01 

0.01 

0.01 

0.01 

0.01 

Oil,  waste,  and  water  j  0.15 
Interest    and    depreciation 

0.15 

~-'5 

0.15 

o  028 

0.15 

0.15 

0.15 

0.15 

0.15 

0.15 

Ditto  electric  plant  |  0.057 
Ditto  building  i  0.028 

0:026 

0.044 

0.033 

-.028 

o'oii 

o'oi 

O.OII 

o'oii 

o'oii 

O.OII 

For  this,  form  Table  II.,  showing  the  elements  in  the  cost 
of  one  horse-power  in  stations  of  various  capacity — from  100 
to  6,000  horse-power.  Engineers  and  dynamo  men  are  as- 
sumed to  receive  40  cents  per  hour,  and  to  superintend  a 
maximum  of  1,000  horse-power.  This  would  produce  in 
some  cases  fractional  engineers,  as  fora  i,5oo-horse-power 
plant ;  but  such  complication  has  been  avoided  by  assuming 
a  constant  value  per  unit  of  power  in  the  pay-roll  element  in 
plants  exceeding  1,000  horse-power.  Firemen  and  helpers 
are  taken  at  30  and  25  cents  per  hour,  respectively.  Super- 
intendence at  30  cents  per  hour  is  apparently  low,  but  is 
equivalent  to  60  cents  for  daylight  hours,  since  the  plant  is 


HIGH-SPEED   SERVICE. 


283 


able  to  run  24  hours  with  the  same  general  superintendence 
as  for  12  hours.  It  is  further  supposed  that  the  total  of  this 
item  will  not  require  increase  until  the  capacity  reaches  3,000 
horse-power,  beyond  which  it  remains  constant  per  unit  of 
power.  As  no  other  element  of  cost  is  supposed  to  vary 
beyond  this  point,  the  table  shows  here  a  minimum  total  cost 
per  unit  and  a  constant  cost  beyond  it. 

Coal  is  assumed  to  cost  $3  per  ton,  and  to  be  consumed 
at  the  rate  of  3.2  pounds  per  electric  horse-power  hour  in  the 
dynamo.  A  slight  error  is  made  in  taking  the  rate  of  con- 
sumption as  constant  while  changing  the  capacity  of  the 
engines.  The  cost  of  the  steam  plant  is  taken  to  vary  from 
$50  per  horse-power,  in  a  small  plant,  to  $20  in  a  plant  of 
1,500  horse-power.  The  dynamo  plant  is  taken  to  vary  from 
$50  to  $20  per  horse-power,  in  going  from  100  to  1,500 
horse-power. 


TABLE    III. 

TOTAI.  COST  OF   ONE   H.    P.    HOUR. 


Output     in    per 
cent,     of    c  a-  Hours  of  work 
pacity      while        per  day. 
working. 

Capacity  of  Station. 

,00 

300 

500 

800 

1,000 

1,500 

2,000 

3,ooo 

J 

4 

42 

is 

.29 
•30 
•52 

.06 

III 

0.9148 
28 

o.Sfo 
0.888 
0.955 

0.835 
0.855 
0-95 

0.830 
0.849 
0.895 

0.825 
0.829 
0.867 

1 

4 

62 

•36 

12 

0.947 

0.88 

0.86 

0.85 

0.83 

90  1 

8 

77 

17 

.98 

O.OI 

0.88 

0.87 

0.853 

3 

.61 

29 

.06 

0.99 

0.94 

0.925 

0.89 

4 

8° 

•45 

18 

.987 

0.92 

0.91 

.88 

0.86 

Bo  •< 

8 

3.06 

o  98 

0.936 

3-42 

•73 

37 

•13 

1.06 

.98 

°-95 

J 

4 

8.19 

•57 

26 

.04 

0.96 

0.925 

.91 

0.89 

7°  •{ 

8 

3-42 

.68 

32 

.09 

.01 

0.952 

•94 

0.91 

I 

3 

3-82 

.90 

48 

.19 

.09 

i.  02 

.01 

0.97 

M 

8 

3-62 
3-85 

36 
44 

!i6 

.01 

.06 

0-975 
•015 

.96 

.00 

0.94 
0.965 

3 

.11 

63 

•30 

•17 

.085 

.07 

1.015 

50  J 

4 
8 

4.22 
4-50 

•95 

it 

.20 

.27 

•045 
.09 

.076 

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6.63 

2.84 

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The  cost  of  buildings  is  taken  to  vary  from  $25  to  $10  per 
horse-power.  This  is  the  most  indefinite  item.  Interest, 
maintenance  and  taxes  are  roundly  assumed  at  10  per  cent, 
per  annum  on  the  whole  plant. 


284  THE    ELECTRIC    RAILWAY. 

With  Table  II.  as  a  basis,  Table  III.  has  been  calculated, 
giving  the  total  cost  per  horse-power  hour  in  stations  of 
various  capacities,  working  at  various  percentages  of  their 
full  capacity  and  for  24,  18  and  ^^hours  per  day,  respect- 
ively. 

A  glance  at  the  table  shows  that  in  a  loo-horse-power  plant 
the  cost  varies  from  2.42  cents  for  a  24 -hour  run  at  full 
capacity,  to  8.06  cents  for  a  3<D-per-cent.  output  continued 
only  12  hours  per  day. 

This  extreme  case  would  doubtless  be  ameliorated  by 
dropping  the  superintendence  and  combining  engineer  and 
fireman — though  to  this  the  unions  might  object.  This 
capacity  is  smaller,  however,  than  need  be  considered. 

The  minimum  cost  given  by  the  table  is  0.816  cent;  this 
is  for  a  3,ooo-horse-power  plant,  working  at  full  capacity  24 
hours  per  day. 

The  next  element  of  cost — that  of  the  conductors  for  the 
current — is  obtained  from  Table  IV.,  showing  the  investment 
in  dollars  for  the  copper  required  to  transmit  one  horse-power 
a  distance  of  one  mile,  at  varying  initial  and  final  pressures. 
The  constants  for  this  table  were  thus  obtained :  Taking  a 
well-known  line  wire,  it  is  found  that  from  No.  4  to  No. 
ooo  B.  W.  G.  the  average  weight  ratio  of  insulated  to  bare 
wire,  per  unit  of  length,  equals  0.844.  When  bare  copper 
sells  at  15  cents  per  pound  this  insulated  wire  sells  at  20 
cents  to  22.5  cents  on  the  copper  alone,  when  insulated.  If, 
therefore,  we  take  copper  at  25  cents  per  pound  we  provide 
for  a  very  good  insulation.  The  cost  of  one  mil-mile  is  thus 
found  to  be  $0.004.  Combining  this  with  the  familiar  for- 
mula 
Q  -^  _  16,600  X  h.  p.  transmitted  X  distance  in  feet. 

~  E.  M.  F.  at  motor  X  volts  lost  X  motor  efficiency' 
the  tabulated  values  have  been  determined  from  the  resulting 
formula : 

Cost-       76°'32°  m 

-  (E^Tvyv 

in  which  E  =  E.  M.  F.  at  station,  V  =  volts  lost  on  line ;  motor 
efficiency  is  taken  at  90  per  cent,  and  distance  at  5,280  feet. 
The  tabular  figures  give  the  investment.  To  reduce  to  actual 


HIGH-SPEED    SERVICE.  285 

cost  per  horse-power  hour,  the  rates  of  interest  and  depreci- 
ation and  the  ratio  between  power  transmitted  and  power 
possible  to  be  transmitted  must  be  had.  For  one  year  the 
possible  horse-power  hours  =  365  X  24.  Take  annual  inter- 
est and  depreciation  at  1-16  the  investment  and  ratio  of  actual 
to  possible  power  transmitted  per  annum  at  i.o,  0.8,  0.6,  0.4, 
0.2,  o.  i ,  0.05,  then  the  divisor  of  the  tabular  number  becomes 
140,160,  112,128,84,096,  52,064,  28,032,  14,026  and  7,008, 
respectively. 

It  remains  to  obtain  values  for  the  distance  of  transmission. 

Let  n  =  number  of  miles  of  line  supplied  from  one  station. 

h  =  horse-power  required  for  unit  locomotive. 

K  =  maximum  number  locomotives  per  mile  at  any  time. 

n  h  K  =  total  power  to  be  transmitted  at  time  of  K. 

A  =  percentage  of  dynamo  power  lost  on  line. 

n  hK 

=  maximum  power  to  be  generated. 

=  lost  on  line. 

b  =  cost  in  cents  of  generating  one  horse-power  hour  in 
station. 

r  =  ratio  of  average  power  required  to  maximum  power 
required. 

L  —  interest  and  depreciation  on  supporting  structure. 

This  last  may  be  omitted  from  the  calculation  determining 
division  of  line  into  sections,  since  it  remains  the  same  what- 
ever that  division  may  be.  Omitting  this,  the  expression  for 
cost  of  transmission  becomes : 

760,320  n3  h  K  r  bnhKA 

~~  (E  —  V)Vx  140, 160   '    r  (100 —  A)  100 
_5.42nshKr  bnhKA 

:  ~(E  _  V)  V     *  r  (loo  — A)  100 

Supposing  that  the  time  schedule  of  trains,  horse-power 
required  per  train,  and  efficiency  of  motors  be  known,  and 
that  the  initial  E.  M.  F.  be  in  all  cases  taken  as  high  as  the 
state  of  the  art  permits,  the  only  variables  remaining  in  this 
expression  are  n,  b,  and  A.  This  latter,  the  value  for  the 
drop  on  the  line,  will  generally  be  determined  by  conditions 
other  than  those  of  strictest  economy  as  shown  by  getting  a 


286 


THE    ELECTRIC    RAILWAY. 


minimum  value  for  cost  of  transmission.  We  must  have  a 
reasonably  uniform  E.  M.  F.  all  along  the  line,  in  order  that 
the  motors  may  work  satisfactorily.  It  will  not  be  wide  of 
the  mark  to  assume  10  per  cent,  as  a  limiting  variation  of 
line  potential.  This  is  the  figure  generally  assumed  in  cal- 
culating wire  for  street  railways. 

The  cost  of  one  horse-power  hour,  b,  must  vary  with  the 
capacity  and  conditions  of  working  of  the  station ;  hence  it 
is  a  function  of  n—i.e.,  length  of  unit  section,  of  A,  and  of 
that  inexpressible  variable — the  conditions  of  the  service. 
This  stands  in  the  way  of  obtaining  any  perfectly  general 
definite  expression  for  n,  which,  but  for  this,  would  result 
from  placing  the  first  differential  co-efficient  of  C,  with  respect 
to  n,  equal  to  zero,  and  solving  to  find  the  value  of  n  giving 
a  minimum  value  for  C.  If  trains  be  run  at  very  short  inter- 
vals, increase  of  n  would  be  followed  by  proportional  increase 
in  capacity  of  station ;  but,  as  above  shown,  this  need  not  go 


g   3.5 
§ 
"C  3. 


CAPACITY  IN  HORSE  POWER 
FIG.  117.— VARIATION  OF  COST  OF  CURRENT  WITH  CAPACITY  OF  STATION. 

beyond  3,000  horse-power  unless  the  service  be  so  heavy  as 
to  require  practically  contiguous  stations  of  that  capacity. 
If  we  suppose  a  case  of  this  short  interval  service,  so  short 
that  a  change  in  n  will  not  be  followed  by  any  change  at  the 
station  in  the  relation  between  maximum  capacity  and  aver- 
age output,  or  in  the  number  of  working  hours,  but  only  in 


HIGH-SPEED    SERVICE. 


28; 


the  normal  capacity,  the  relation  between  b  and  n  for  two 
cases  of  average  output  and  working  hours  is  shown  by  Fig. 
117.  The  equation  of  the  50  per  cent,  curve  from  200  to  i  ,000 
horse-power  seems  to  be  very  nearly 

_  n2  —  QSn  -f-  i  ,000 

12  (n  —  100) 

If  the  trains  be  run  at  very  long  intervals  we  may  require 
no  greater  station  capacity  for  20  than  for  10  mile  sections; 


.5       .6       .7        .8        .9      1-Ct.    1.1     1.2     1.3      1.1      1.5     1.8     1.7 
COST  PER  H.P.PER  HOUR  RUN 

FIG.  n8.— VARIATION  OF  COST  OF  CURRENT  WITH  CAPACITY  OF  STATION. 

but  the  relation  of  output  to  normal  capacity  will  vary,  and 
possibly  also  the  number  of  hours  during  which  the  working 
force  would  require  to  be  kept  on  pay. 

Taking  the  case  of  a  change  in  average  output  only  for  a 
i,ooo-horse-power  station,  we  have  the  curves  in  Fig.  1 18  for 
24,  1 8,  and  12  hours'  work.  The  equations  are  nearly  of  the 
same  form,  and  are  approximately  the  equations  of  arcs  of 
circles  referred  to  an. origin  outside  the  circle.  But  each 
would  contain  different  constants,  and  would  vary  more  or 
less  from  the  exact  formula  for  the  circle. 

If  in  the  application  to  a  particular  case  the  algebraic 
expression  for  b  above  given,  Or  any  other  resulting  from 
any  of  the  possible  progressions  through  Table  III.,  be  sub- 
stituted in  equation  (2),  we  may,  by  differentiation,  solve  that 
particular  case  for  the  most  economical  value  of  n.  If  the 
relation  between  b  and  n  cannot  be  algebraically  expressed, 
then  the  proper  value  for  n  may  be  determined  by  a  few  trial 
values,  the  corresponding  values  of  b  being  taken  from  the 
table. 


288  THE   ELECTRIC    RAILWAY. 

For  the  present  purposes  of  comparison  we  will  assume  a 
case  not  more  favorable  than  might  often  be  met  on  busy 
steam  lines — i.e.,  a  station  of  2,000  horse-power  normal 
capacity,  working  18  hours  per  day  at  40  per  cent,  of  its  nor- 
mal output,  the  cost  per  horse-power  being  1.25  cent. 

To  obtain  the  cost  of  the  line  we  will  assume  that  the 
average  distance  of  transmission  is  five  miles.  This  would 
correspond  to  one  station  for  every  twenty  miles  of  road. 
We  will  also  assume  5,000  volts  initial  E.  M.  F.  and  10  per 
cent.  "  drop. "  From  Table  IV.  the  copper  investment  is  found 
to  be  34  cents  for  one  mile.  Then  for  five  miles  the  invest- 
ment equals  $8.50.  Making  assumptions  as  to  service  cor- 
responding to  those  for  the  station,  we  have  cost  for  one 
horse-power  equaling  $8.50  -=-  20,000  :=  0.042  cent. 

The  structure  for  carrying  the  conductors  may  be  built  for 
$2,000  per  mile.  Interest  and  depreciation  would  then  be- 
come §200  per  annum.  This  total  is  almost  wholly  inde- 
pendent of  the  power  transmitted;  hence  the  cost  per  unit  of 
power  will  vary  inversely  with  the  number  of  units  transmit- 
ted. Assuming  a  constant  distribution  of  one  joo-horse-power 
train  for  every  20  miles  of  line,  we  have  the  cost  of  this  item 
for  one  horse-power  hour : 

20,000  ~  365  X  24  X  25  =  0.09  cent. 

Reaching  the  locomotive,  we  must  add,  supposing  an  aver- 
age output  of  500  horse-power,  0.08  and  0.06  cent,  respect- 
ively, for  driver  and  his  assistant.  The  latter  is  necessary 
only  as  a  substitute  for  his  principal  in  case  of  emergency, 
but  as  such  he  would  doubtless  always  be  placed  on  trains  of 
considerable  value. 

Repair  on  electric  locomotives  is  not  as  yet  well  defined. 
That  the  repair  bill  must  be  far  less  than  in  the  case  of  steam 
locomotives  follows  almost  necessarily  from  the  great  reduc- 
tion in  the  number  of  parts,  especially  of  moving  parts. 

From  Mr.  Arthur  Wellington's  very  valuable  work  on 
railways,  we  take  the  figures  showing  percentage  distribution 
of  locomotive  repairs  by  parts. 

Boiler,  20  per  cent. ;  running  gear,  20  per  cent. ;  machin- 
ery, 30  percent.;  lagging  and  painting,  12  percent.;  smoke- 
box,  etc.,  5  per  cent.;  tender  (running  gear,  10  per  cent.; 


HIGH-SPEED    SERVICE. 


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2g0  THE    ELECTRIC    RAILWAY. 

body  and  tank,  3  per  cent.),  13  per  cent.;  total,  100  per 
cent. 

Of  these  items  we  may  at  once  and  with  certainty  strike 
out  boiler,  smoke-box,  etc.,  and  tender — thus  dropping  38 
per  cent,  of  the  total.  Having  no  boiler  to  carry,  the  running 
gear  will  be  less  in  quantity. 

The  wear  will  be  less,  due  to  the  use  of  rotary  instead  of 
reciprocating  effort.  It  will  then  be  fair  to  reduce  this  item 
by  half,  making  another  saving  of  10  per  cent.  So  in  the 
machinery  item  there  can  be  no  question  that  with  the  rapid 
advance  toward  slow-speed  motors,  reducing  gear,  and  sound 
insulation  methods,  the  great  advantage  of  having  only  one 
moving  part  in  the  motor  itself  must  operate  to  reduce  very 
largely  the  repair  figure,  probably  to  half  its  value  in  a  steam 
locomotive,  leaving  it  at  15  per  cent.  In  lagging  and 
painting,  the  omission  of  boiler  and  other  parts  must 
again  effect  a  reduction,  say  to  6  per  cent.  The  total 
reduction  thus  plainly  indicated  must  be  then  very  nearly 
70  per  cent. 

The  actual  cost  of  repairs  to-day  on  steam  locomotives  isr 
on  the  Pennsylvania  Railroad,  nearly  0.75  cent  per  horse- 
power hour.  Reducing  as  above,  this  figure  becomes  0.22 
cent  for  electric  traction.  This  refers  to  engines  of  consid- 
erable power,  say  from  400  to  1,000  horse-power  capacity. 
The  figure  for  both  steam  and  electric  motors  w^ould  go 
up  for  smaller  powers. 

The  interest  charge  results  from  considering  the  cost  of 
an  electric  locomotive  as  $50  per  horse-power,  and  the  duty 
as  six  hours  per  day,  full  capacity.  The  average  duty  of 
steam  locomotives  is  only  about  three  hours.  The  higher 
figure  results  from  a  smaller  number  of  repairs  necessary, 
due  to  greater  simplicity  of  parts.  Then 

^   ,-  5O.OO  X  O.o; 

Interest  for  h.  p.  hour  =  - — -~-  =  o.  1 1  cent. 

Before  summarizing  we  must  know  something  of  the 
efficiency  of  the  system.  If  the  locomotive  be  of  90  per 
cent.,  or  80  per  cent.,  or  60  per  cent,  efficiency,  we  must 
generate,  respectively,  1.25,  1.4,  and  1.85  horse-power  hour 
in  the  station  for  every  horse-power  hour  actually  delivered 


HIGH-SPEED    SERVICE. 


29I 


to  drivers  (line  loss  being  supposed  constant  at  10  per  cent.). 
We  should  then  have  in  the  station  1.56,  1.75,  and  2.30 
cents,  respectively.  Then,  for  total: 


Station  
Conductor  system  
Structure  for  same  

1.56 
0.042 
0.09 

i-75 
0.04 
o  09 

2.30 
0.04 

O  OQ 

Wages  
Repairs 

o.  14 

o  '>'> 

0.14 

0.14 

Interest  

O.  I  I 

0.  I  I 

0.  I  I 

Totals  

2.16 

2.  ^C 

2  QO 

Of  the  whole  amount  it  is  to  be  noted  that  the  station  item 
is  three-fourths.  Taking  the  most  favorable  case  shown  by 
the  table — 3,000  horse-power  capacity,  working  for  24  hours 
at  100  per  cent,  of  capacity — those  figures  become  1.5,  1.62, 
and  2.00  cents,  nearly,  the  reductions  in  the  other  items 
being  still  a  little  indefinite,  without  making  another  series 
•of  independent  assumptions. 

The  cost  of  one  horse-power  hour  exerted  by  steam  loco- 
motives is  to  be  obtained  only  by  some  circumlocution,  the 
reports  of  cost  being  based  on  train-miles.  As  quoted  by 
Wellington,  the  coal  consumed  per  passenger  train-mile  on 
the  Pennsylvania  Railroad  is  very  closely  50  pounds,  and  an 
average  performance  will  show  5  pounds  coal  per  horse-power 
liour  while  under  way.  This  shows  that  one  train-mile  equals 
10  horse-power  hours.  The  coal  consumption  of  a  freight 
train-mile  is  much  higher,  but  the  divisor  would  also  be 
higher,  on  account  of  the  greater  number  of  stops,  in  backing 
and  switching,  and  greater  delays  while  on  a  trip,  thus 
increasing  waste  of  coal. 

Again,  the  Pennsylvania  Railroad  reports  show  a  cost  of 
fuel  per  train-mile  of  5  cents.  The  cost  of  coal  to  that  com- 
pany, as  nearly  as  we  can  learn,  is  about  $1.50  per  ton. 
Hence  it  would  appear  that  66  pounds  per  train-mile  are 
consumed.  As  the  terminal  losses  of  fuel  and  delay  (getting 
up  steam  and  drawing  fires,  etc.)  are  known  to  be  in  the 
neighborhood  of  25  per  cent,  of  the  total  consumption,  we 
have  6.6  (pounds)  as  the  divisor,  and  the  same  ratio  again 
appears.  The  cost  of  one  train-mile — as  to  motor  power 


292  THE    ELECTRIC    RAILWAY. 

alone is  given  by  the  Pennsylvania  Railroad  as  22  cents. 

And  this  is  practically  equal  to  the  average  for  the  United 
States.  The  itemized  statement  is  very  carefully  made  up, 
and  seems  to  cover  everything  except  interest  on  the  engine 
investment. 

Knowing  the  annual  mileage  per  locomotive  to  be  about 
20,000  and  the  cost  to  be  $10,000,  interest  charge  per  train- 
mile  (not  quite,  but  nearly,  equivalent  to  engine  mile)  be- 
comes 2.7  cents.  Total  cost  becomes  24.7  cents,  or  2.47 
cents  per  horse-power  hour. 

We  may  safely  use  this  figure  in  the  comparison  to  be 
made,  since  any  positive  error  in  the  calculation  of  coal  per 
horse-power  hour  or  negative  error  in  horse-power  hours  per 
train-mile  will  be  offset  by  the  difference  in  cost  of  coal  per 
ton  to  the  Pennsylvania  Railroad  as  compared  with  the  value 
assumed  in  Table  III. 

At  $3,  instead  of  $1.50,  the  fuel  item  would  be  10  cents- 
and  the  total  motive  power  29.5  cents.  Leaving  the  statis- 
tics of  actual  cost,  we  may  reach,  by  the  method  of  Table 
III.,  nearly  the  same  figure,  considering  the  locomotive  as  a 
i,ooo-horse-power  steam  plant  of  low  first  cost,  burning  6 
pounds  of  coal  per  horse-power  hour,  and  working  at  one- 
third  capacity  for  about  three  hours  per  day.  The  result 
thus  reached  is  about  10  per  cent,  higher,  but  the  2.47  cents 
seem  more  reliable. 

These  values  multiplied  into  the  corresponding  values  in 
the  last  nine  columns  of  Table  I.  give  the  following  values  of: 

Power  units,  steam          cost  per  unit,  steam. 
: <y/ £ l 

Power  units,  electric       cost  per  unit,  electric. 

This  value,  Table  V.,  when  greater  than  unity  indicates 
greater  economy  by  electricity  than  by  steam,  and  vice  versa. 

A  glance  at  the  table  shows  the  dominating  necessity  of 
increasing  the  efficiency  of  the  mechanism  delivering  energy 
from  the  electric  line  to  the  vehicle.  We  cannot  count  upon 
a  higher  efficiency  than  90  per  cent,  for  the  motor.  Hence, 
save  in  the  case  of  putting  the  armature  directly  on  the  axle, 
we  cannot  hope  to  reduce  the  total  loss  to  less  than  20  per 
cent. — a  case  permitting  one  set  (i.e.,  two  gears)  of  spur 
gearing  between  armature  and  axle.  As  the  ordinary  rela- 


HIGH-SPEED    SERVICE. 


293 


tion  beween  tonnage  and  resisting  area  will  lie  between  the 
second  and  third  columns  of  each  efficiency  table,  it  appears 
that  with  a  20  per  cent,  loss  electricity  becomes  cheaper  than 
steam  at  about  70  miles  per  hour,  the  frequency  of  service 
being  such  as  is  assumed  above. 


Ratios  of  cost  of  motive  power  =       cosi  ^  steam 

cost  by  electricity 


Efficiency  of  electric 
engine. 

10  per  cent. 

20  per  cent. 

40  per  cent. 

Tonnage  and  area 

relation. 

2&3 

2&  5        2  &8 

2&3 

2&5 

2&8 

2&3 

2&S 

2&8 

Speed. 

•  5 
•  9 
•   5 

•57 

.16 
.19 
•24 

:l 

0.92 
o-95 

1.  00 

0.85 

0-95 

1.  00 

0.85 
0.95 
0.95 

0.56 

3 

o^57 
0.58 

?1 

1-36 

p  p  p  p  p  p  p 

20 
40 
60 
80 
100 
120 
140          ^ 

-94 
.82 

•3 

i 

11 

1.20 

I.I3 

0.66 
0.80 

In  the  case  of  40  per  cent,  loss  our  new  agent  betters  the 
old  only  at  140  miles  per  hour.  And  yet  this  loss — 40  per 
cent. — is  about  the  best  we  do  with  our  present  systems  of 
electric  street  car  propulsion. 

Considering  the  very  short  life  of  the  art,  these  results  are 
excellent.  Indeed,  excellence  is  shown  in  the  mere  fact  of 
success  in  competing  with  horses  under  conditions  very  trying 
for  any  mechanism  not  made  of  india-rubber  or  whit-leather. 
How  great  that  success  has  been  we  need  not  here  proclaim. 
But  the  steam  locomotive  is  a  foeman  more  worthy  of  our 
steel,  or,  rather,  of  our  annealed  soft  iron  and  99  per  cent, 
conductivity  copper. 

Consideration  of  all  that  precedes  leads  to  the  following 
general  conclusions: 

1.  A  slow-speed  armature  placed  on  the  car  axle  would 
place  the  electric  motor  in  the  lead  at  all  service  speeds. 

2.  For  speeds  above  70  miles  per  hour  an  electric  motor  of 
90  per  cent,  efficiency,  working  through  gearing  of  90  per 
cent,  efficiency,  would  prove  more  economical  than  the  steam 
locomotive — save  in  cases  of  very  infrequent  service  on  very 
long  lines. 

3.  On  lines  for  heavy  traffic  steam   would  be  more  eco- 


294  THE    ELECTRIC    RAILWAY. 

nomical  than  electricity  if  motor  and  gearing  have  a  combined 
efficiency  as  low  as  60  per  cent.,  up  to  100  miles  per  hour. 

4.  At  speeds  of  100  miles  per  hour  and  upward  neither 
steam  at  90  per  cent,  nor  electric  apparatus  at  60  per  cent, 
efficiency  is  commercially  practicable. 

5.  Inasmuch  as  the  saving  of  coal  in  stationary,  as  com- 
pared with  locomotive,  engines  is  one  of  the  chief  causes  of 
the  greater  economy  of  electric  propulsion  at  any  speed  this 
advantage  will  increase  with  that  difference  and  also  with  the 
price  of  coal. 

6.  Any  cause  other  than  inefficiency  of  motor  which  in- 
creases the  power  required  to  haul  a  ton  of  freight  increases 
the  advantages  of  electricity,  since  it  enlarges  the  value  of 
the  coal  difference  and  the  dead-weight  difference. 

Thus,  bad  roadways  and  large  areas  exposed  to  atmospheric 
resistance,  as  in  street-railway  work,  lower  the  spee<J  at  which 
electric  motors  of  any  efficiency  become  cheaper  than  steam. 

7.  In    descending  to   small  locomotive   units  the  electric 
motor  loses  less,  relatively,  of  its  advantage — another  reason 
for  success  on  street  lines. 

8.  Multiplying  the  number  of  motors  should  be  as  far  as 
possible  avoided. 

9.  In  special  cases  cleanliness  and  compactness  of  electric 
machinery  may  be  of  great  value ;  in  case  of  very  frequent 
stops  the  possibility  of  returning  to  the  line  the  energy  now 
wasted  in  brakes  may  be  of  considerable  value.     This,  how- 
ever, can  be  obtained  only  by  sacrifice  in  the  matter  of  dead 
weight,  as  normal  working  is  implied  to  be  at  comparatively 
low  magnetization.     Loss  due  to  low  efficiency  in  starting  can 
scarcely  be  avoided,  either  in  steam  or  electric  engines. 

10.  Other  minor  pros  and  cons  may  be  enumerated,  but, 
considering  the  general  economic  results  of  the  two  systems, 
we  reach  no  more  definite  conclusions. 

While  only  one  condition  of  station  working  has  been 
taken  for  final  comparison,  that  case  is  an  average  one,  and 
comparative  results  would  be  but  slightly  affected  by  ordinary 
variations.  Extreme  cases  may  be  readily  determined  from 
the  tables  and  formulae  presented. 

1 1 .  Some  difference  of  opinion  as  to  the  proper  values  for 


HIGH-SPEED    SERVICE.  295 

the  various  constants  is  to  be  expected,  but  these  differences 
taken  all  along  the  line  would  probably  nearly  balance  between 
positives  and  negatives,  leaving  the  general  results  and  the 
method  unchanged. 

Whether  these  conclusions  be  accepted  or  not,  we  believe 
the  tables  and  formulas  here  presented  will  be  found  valuable. 

Consulting  Table  V.,  we  find  that  rapid  transit  service  for 
large  cities  can  be  accomplished  electrically  with  a  saving  in 
motive  power  of  about  20  per  cent,  on  the  cost  by  steam. 
This  supposes  the  electric  motor  to  have  an  efficiency  of 
about  90  per  cent.,  at  30  miles  per  hour,  and  contemplates 
the  construction  of  the  armature  concentric  with  the  axle.  In 
respect  to  this  point  there  would,  at  this  writing,  be  little,  if 
any,  difference  of  opinion.  It  should  be  added  that  in  con- 
sidering city  service  a  more  favorable  case  of  station  expense 
might  be  assumed  than  that  which  has  entered  into  Table  V. 
There  we  have  taken  a  total  capacity  of  2,000  horse-power 
working  at  40  per  cent,  of  that  capacity  during  18  hours,  the 
cost  per  horse-power  hour  being  1.25  cent. 

But  in  the  case  of  city  service  the  load  will  be  tolerably 
uniform  and  the  station  capacity  may  be  so  determined  that 
the  average  output  may  be,  say,  60  per  cent,  of  the  capacity. 
We  might,  indeed,  fairly  take  i  cent  per  horse-power  hour 
for  the  station  cost.  This  assumption  would  be  followed  by 
an  increase  of  about  one-eighth  in  the  figures  given  for  u  10 
per  cent,  loss"  in  Table  V.  We  might,  then,  fairly  say  that 
an  economy  of  30  per  cent,  may  be  had  over  the  cost  of 
motive  power  by  steam.  Now,  in  the  average  rapid  transit 
system  the  motive  power  expense  may  be  taken  at  abotit  one- 
third  of  the  total  operating  expense.  On  this  total,  then,  the 
saving  may  be  said  to  be  about  10  per  cent. 

The  conclusions  here  drawn  from  the  tables  above  given 
have  been  checked  by  careful  detailed  estimates  made  for 
special  projects  now  on  foot  in  Chicago,  111.,  and  by  engineers 
not  familiar  with  the  tables.  The  results  were  very  nearly 
identical,  tending  to  show  that,  at  least  in  all  general  discus- 
sion of  such  work,  very  satisfactory  guidance  is  given  by  the 
figures  here  presented. 

Concerning  speeds  considerably  beyond  those  now  com- 


296  THE    ELECTRIC    RAILWAY. 

monly  attained  by  steam,  no  experiments  have  been  made 
and  reported  save  those  made  by  one  of  the  authors  at  Laurel, 
Md.*  The  work  was  done  for  the  Electro- Automatic  Transit 
Company  of  Baltimore,  Md.  The  organizer  of  this  company 
was  Mr.  David  G.  Weems.  Lack  of  means  has  thus  far  stood 
in  the  way  of  accomplishing  on  a  proper  scale  the  demon- 
stration required  in  order  that  the  world  may  become  familiar 
with,  and  practically  interested  in,  the  practicable  increase 
of  speed  of  transportation  up  to  125  or  150  miles  per  hour. 

In  the  experiments  above  referred  to  a  car  about  30  inches 
high  by  24  inches  wide  by  20  feet  long,  carrying  two  motors 
with  their  armatures  keyed  directly  to  the  axles  and  weighing 
about  2.5  tons,  was  driven  around  a  circular  track  (2 8 -inch 
gauge,  2  miles  in  circumference)  at  a  final  speed  of  about 
1 1 5  miles  per  hour.  Control  was  effected  from  the  power 
station,  placed  inside  the  circle.  The  voltage  of  the  line  was 
500.  An  upper  rail  carried  on  a  framework  built  over  the 
track  served  as  one  side  of  the  circuit,  the  lower  track  rails 
and  earth  as  the  return  circuit. 

Current  was  received  from  the  upper  rail  through  an  up- 
ward bearing  brush.  The  track  was  of  exceedingly  light 


FIG.  119. -PLAN  AND  ELEVATION  OF  EXPERIMENTAL  CAR.-WEEMS  SYSTEM. 

construction — quite  unfit  for  the  work  attempted  to  be  done. 
Figs.  1 19  and  120  show  the  car  and  station.     Valuable  infor- 


*  See  "Report  of  High  Speed  Electric  Railway  Work,"  by  O.  T.  Crosby.      Read  before 
the  American  Institute  of  Electrical  Engineers,  February  24,  1891. 


HIGH-SPEED    SERVICE.  297 

mation,  however,  was  obtained  concerning  atmospheric  and 
tonnage  resistance. 

In  the  American  Institute  paper  above  referred  to  these 
results  were  reported  quite  fully,  and  plans  were  shown  for 


FIG.  120.— STATION  AND  TRACK  AT  LAUREL,  MD.-WEEMS  SYSTEM. 

a  passenger  service  or  passenger  and  mail  service  at  125 
miles  per  hour.  Since  nothing  more  definite  has  yet  been 
done  in  this  direction  we  can  only  quote  some  of  the  con- 
clusions reached,  and  further  refer  the  reader  to  the  paper 
itself  for  details. 

A.  For  purposes  of  demonstration  it  was  proposed  to  the 
company  that  they  should  build  a  track  about  4  miles  (not 
less)  in  circumference,  and  should  run  thereon  a  train  of  two 
or  three  cars  drawn  by  one  locomotive.  Calculations  were 
based  on  the  following  data: 

(1)  A  speed  of   150  miles  per  hour  on  a  level  was  to  be 
aimed  at. 

(2)  Cross-section  of  car  should  be  a  minimum  consistent 
with  the  seating  of  passengers.     This  was  taken  at  6  feet  by 
5  feet — 30  square  feet  (crowning  higher  along  middle  of  car). 

(3)  Gauge  of  track  should  be  standard — 4'  8.5". 

(4)  Character  of  track  should  be  simply  the  best  that  art 
could  contrive,  rails  to  weigh  from  65  to  90  pounds  per  yard. 

(5)  Electromotive  force    should  be  as  high  as  the  art  of 
insulation  would  permit. 

(6)  Whatever  might  be  the  number  of  cars  in  a  train,  all 
were  to  be  so  connected  as  to  present  a  continuous  exterior, 
thus  presenting  only  one  cross-section  to  the  atmosphere. 


298 


THE    ELECTRIC    RAILWAY. 


(7)  Atmospheric  resistance  at  150  miles  per  hour  would  be 
taken  at  15  pounds  per  square  foot  of  cross-section,  a  wedge 
or  parabolic  locomotive  head  being  used.     This  value  is   50 
per  cent,  in  excess  of  that  indicated  by  experiments. 

(8)  Traction  co-efficient,  exclusive  of  air  resistance,  would 
be  taken  at  150  miles  per  hour  to  be  25  pounds  per  ton — this 
for  reasons  set  forth  previously. 

From  the  two  resistance  co-efficients  just  given,  it  followed 
that  for  every  square  foot  of  cross-section,  regardless  of 
weight,  6  horse-power  would  be  required,  and  for  every  ton 
of  weight,  regardless  of  cross-section,  10  horse-power  must 
be  supplied. 


FIG.  i2i.— HALF  SECTION  OF  MOTOR  FOR 
HIGH-SPEED  SERVICE. 


FIG.  122.— HALF  PLAN  OF  MOTOR  FOR 
HIGH-SPEED  SERVICE. 


For  a  locomotive  of  about  600  horse-power,  having  30  square 
feet  cross-section,  the  dead  weight  was  calculated  to  be  about 
1 8  tons.  Steel  cars  of  equal  cross-section  were  designed, 
weighing,  empty,  about  5  tons,  with  a  carrying  capacity  of 
about  5  tons. 

The  important  question  as  to  power  required  could  then 
be  tabulated  thus : 


Locomotive  alone 

Locomotive  and  one  car  loaded . '.  .  .  .  .  . 

Locomotive  and  two  cars  loaded 

Locomotive  and  three  cars  loaded 


150  miles 
per  hour. 

360  H.  P. 
460 

560     " 
760     " 


120  miles 
per  hour. 

288  H.  P. 
369      " 
446      " 
528      " 


HIGH-SPEED    SERVICE. 


299 


To  perform  the  work  here  indicated  two  motors  were  to 
be  provided,  one  armature  directly  on  each  of  the  two  axles 
of  the  locomotive  car.  These  motors,  outlined  in  Figs.  121- 
124,  were  of  the  Manchester  type.  They  were  supposed 
to  be  at  first  connected  in  arc  across  a  i,5OO-volt  circuit,  each 
taking  about  130  to  150  amperes  and  delivering  about  250  to 
300  horse-power.  Should  it  be  desired  to  experiment  with 


FIG.  123.— HALF  LONGITUDINAL  SECTION  OF  ELECTRIC  LOCOMOTIVE. 

higher  line  potential,  the  motors  in  series  would  permit  3,000 
volts  to  be  easily  tried.  The  armatures  of  the  Gramme  type 
were  30  inches  outside,  23  inches  inside,  diameter.  The  ar- 
mature conductors  were  to  be  of  about  40,000  circular  mils 
cross-section,  or  from  500  to  600  c.  m.  per  ampere.  Many 
successful  machines  designed  to  work  indoors  go  as  low  as 


3oo 


THE   ELECTRIC    RAILWAY. 


this  figure,  and  since  the  dissipation  of  heat  must  in  such 
case  proceed  more  slowly  than  in  the  case  here  considered, 
the  figure  seemed  very  safe.  Moreover,  it  was  intended  to 
introduce  a  blast  of  air  from  the  car  front,  which  should  con- 
tinuously flow  through  the  open  center  of  the  armature. 


FIG.  124.— HALF  TRANSVERSE  SECTION  OF  ELECTRIC  LOCOMOTIVE. 

How  far  the  rate  of  dissipation  would  in  practice  be  carried 
by  such  means  cannot  now  be  known,  but  all  recent  evidence 
goes  to  show  that  the  heat  capacity  would  be  much  increased. 
The  cross-section  of  core  in  the  armature  was  3.5*  X  40"  = 
140  square  inches  gross,  or,  deducting  1 5  per  cent,  for  paper 


HIGH-SPEED    SERVICE.  301 

insulation  between  disks,  and  8  per  cent,  for  conductor  slots 
cut  in  periphery,  no  square  inches  net.  Through  this  ar- 
mature it  was  desired  to  force  22,000,000  lines  (C.  G.  S.  units) 
or  100,000  per  square  inch  =  15,200  per  square  centimeter. 
The  magnet  coils  of  the  two  armatures  were  calculated  to 
be  in  series  with  each  other,  but  in  shunt  with  respect  to  the 
two  armatures.  This  variation  from  present  street-car  prac- 
tice was  thought  to  be  justified  by  the  following  considerations : 

First,  no  system  of  commutation  could  obviate  the  need 
of  a  considerable  external  resistance,  which  could  be  easily 
made  sufficient  within  itself  for  speed  control;  second,  the 
maximum  torque  for  a  given  armature  current  is  always 
desirable  and  can  best  be  obtained  by  permanent  saturation ; 
third,  this  constant  and  maximum  magnetization  would  tend 
to  diminish  sparking — an  evil  to  be  specially  avoided  in  long- 
distance work,  involving  continuous  runs  of  several  hours. 

While  it  was  thus  intended  to  use  shunt  coils  at  first,  a 
little  experience  would  soon  demonstrate  whether  the  advan- 
tage lay  with  this  or  the  series  winding. 

The  commutator,  Fig.  124,  was  designed  to  be  23  inches  in 
diameter,  which  would  of  course  give  rise  to  a  very  high 
speed  relative  to  the  brushes.  It  was  thought  better  to  face 
the  mechanical  trouble  that  might  be  connected  with  great 
circumferential  speed  rather  than  to  diminish  the  diameter 
"by  decrease  of  sections,  since  this  in  turn  might  produce 
sparking. 

Without  going  into  the  mechanical  details  of  the  commu- 
tator, we  may  add  that  a  single  bar  could  be  taken  out  or 
replaced  without  removal  from  the  shaft. 

The  rheostat  for  the  armature  circuit  was  designed  to  be 
of  iron  wire,  with  the  expectation,  however,  of  experimenting 
also  with  liquid  or  carbon  resistance.  The  resistance  and 
heat  capacity  of  this  main  line  rheostat  were  determined  with 
reference,  first,  to  the  current  necessary  for  starting ;  second, 
to  currents  needed  for  maintaining  low  speeds. 

A  small  rheostat  and  a  condenser  were  designed  to  be 
placed  in  the  circuit  of  the  magnet  coils,  and  a  rheostat  also 
in  the  lamp  circuit,  these  resistances  giving  delicate  control. 

The  problem  of  retardation  for  a  mass  of,  say,  40  tons  run- 


202  THE    ELECTRIC    RAILWAY. 

ning  at  1 50  miles  per  hour  is  a  serious  one.  The  Gallon  and 
Westinghouse  tests  indicate  a  very  low  value  for  the  co-effi- 
cient of  friction  between  brake-shoe  and  wheel  at  high 
speeds ;  they  report  it  in  some  cases  at  60  miles  per  hour  as  low 
as  0.04.  As,  however,  it  rapidly  increases  at  lower  speeds, 
an  average  of  o.  i  may  be  taken.  The  total  retarding  effort, 
i.e.',  brake  resistance  and  track  and  atmospheric  resistance, 
must  be  kept  below  that  which  will  just  produce  sliding  of 
the  wheels,  and  the  co-efficient  of  sliding  may  be  taken  on  an 
average  at  0.08  of  the  weight  on  the  wheels.  If,  then,  we 
represent  by  P  the  maximum  allowable  brake  pressure  on 
the  wheels,  by  R  resistances  other  than  brake  friction,  and 
by  W  the  weight  on  braked  wheels,  we  may  wr.ite  the  follow- 
ing inequality :  o.i  P  —  R  <  0.08  W. 

The  value  of  P  should  be  determined  as  that  which,  with 
a  small  margin,  will  satisfy  this  condition  of  inequality. 

Following  this  calculation,  it  was  found  that  a  brake  press- 
ure of  about  5,000  pounds  should  be  applied  to  each  wheel. 
This  was  designed  to  be  produced  by  magnetic  brakes  similar 
to  those  used  by  Mr.  Daft  on  the  New  York  Elevated  Rail- 
way. The  form  and  approximate  dimension  of  those  brakes 
are  shown  in  Fig.  125. 

A  mass  of  80,000  pounds  moving  at  1 50  miles  per  hour  rep- 
resents 64,000,000  foot-pounds  of  energy.  Average  resistance 
due  to  brakes  =  o.  i  X  60,000  —  6,000  pounds.  Average  re- 
sistance from  track  and  atmosphere  for  average  speed  of  75 
miles  =  400  pounds. 

In  addition,  the  motors  may  be  required  to  generate  a  cur- 
rent which  shall  be  wasted  over  the  rheostat.  Since  the 
field  circuit  in  the  case  of  shunt  motors  is  independent,  mag- 
netization may  remain  constant,  and  the  average  E.  M.  F.  of 
i,500-volt  motors  (i.e.,  motors  generating  1,500  volts  E.  M.  F. 
at  1,100  revolutions  per  minute)  would  be,  while  the  train 
was  coming  to  rest,  750  volts.  Make  the  external  resistance 
such  that,  the  two  armatures  being  in  series,  an  average  cur- 
rent of  200  amperes  shall  flow.  Then  the  average  dynamo 
resistance,  in  pounds  =2,000.  Total  retarding  effort  = 
6,000  -f-  400  -J-  2,000  =  8,400  pounds.  Dividing  64,000,000 
by  this  last  quantity,  we  have  7,620  feet  as  the  length  of 


HIGH-SPEED    SERVICE. 


303 


run  in  coming  to  rest,  and  the  time  of  stopping  about  100 
seconds. 

For  the  mechanical  construction  of  the  locomotive  two 
plans  were  contemplated.  One  had  a  12 -foot  rigid  wheel 
base  and  no  pilot  wheels;  the  other  had  a  7-foot  wheel  base 
for  the  drivers  and  a  pony  axle  in  front,  free  to  move  later- 

HALFPLAN 


LONGITUDINAL  SECTION 
FIG.  125.— ARRANGEMENT  OF  ELECTRIC  BRAKE  FOR  HIGH-SPEED  LOCOMOTIVE. 

ally  over  a  certain  distance,  dragging  the  drivers  in  the  same 
direction.  This  is  the  general  principle  of  pilot  wheels,  so 
largely  used  on  high-speed  engines.  The  second  arrange- 
ment is  preferred,  for  in  it  nearly  all  the  weight  goes  on  the 
drivers. 


304  THE   ELECTRIC    RAILWAY. 

In  the  first  design  of  locomotive  car  the  operator  was  to  sit 
between  the  two  motors,  where  also  would  be  placed  the 
controlling  devices.  In  the  second  design  the  operator  would 
be  placed  over  the  pony  axle,  the  devices  being  chiefly  in 
the  cylindrical  or  parabolic  head.  Detailed  drawings  of 
freight  and  passenger  cars  were  completed,  but  need  not 
here  be  referred  to. 

As  to  the  supply  of  current,  it  was  proposed  to  use  the 
double  metallic  system.  This  departure  from  the  ground 
return,  now  so  commonly  employed  in  street-railway  work, 
seems  justified  by  the  following  considerations : 

i  st.  For  a  given  voltage  it  diminishes  the  cost  of  insula- 
tion, per  se. 

2d.   It  diminishes  the  danger  of  accident  within  the  motors. 

3d.   It  diminishes  danger  of  accident  to  workmen. 

4th.  By  being  thus  more  readily  handled  it  is  probable 
that  a  higher  voltage  will  be  found  practicable  than  with  the 
ground  return;  hence,  in  fact,  even  first  cost  might  not  be 
greater. 

As  designed,  the  conductors  were  to  be  placed  in  an  in- 
verted wooden  trough,  attached  to  posts  placed  at  1 2-foot 
intervals  on  each  side  of  the  track.  The  trough  was  to  be 
about  5.5  feet  above  the  ground.  The  conductors  for  each 
side  of  the  circuit  were  to  be  two — one  insulated  and  contin- 
uous, the  other  a  bare,  flat  strip  broken  into  sections,  these 
being  normally  out  of  circuit ;  the  locomotive  trolley  arm 
operating  a  switch  to  throw  out  the  rear  section  and  throw 
into  circuit  the  section  ahead.  Such  a  switch  was  designed 
in  detail. 

As  to  what  the  line  voltage  should  be,  progress  in  the  art 
of  insulation  can  alone  determine.  It  would,  of  course,  not 
be  necessary  on  a  roadway  for  long-distance  travel  to  consider 
the  death-producing  voltage  as  a  limitation. 

In  the  important  matter  of  limiting  curvatures  calculations 
were  made  in  the  ordinary  way,  using  particular  values  for 
weight  and  height  of  center  of  gravity.  A  safe  speed  was 
then  tabulated,  being  just  one-half  the  speed  that  causes  the 
resultant  of  weight  and  centrifugal  force  to  pass  through  the 
outer  rail  of  a  curve.  The  beneficial  effect  of  super-elevation, 


HIGH-SPEED    SERVICE.  305 

neglected   in  the   calculation,   would,  of  course,  practically 
much  increase  the  factor  of  safety. 

The  following  table  resulted  from  the  method  described: 

Safe  speed,  by  rule  above, 
Radius  in  feet.  in  miles  per  hour. 

1,000 • 71 

2,000 98 

3,OOO I  20 

4,000 140 

5,000 158 

6,000 172 

7,ooo 187 

8,  ooo 198 

Of  course,  naught  save  practical  trial  could  determine 
whether  the  assumed  factor  of  safety,  which  is  quite  large 
enough  at  present  speeds,  would  in  fact  be  right  for  the 
higher  speeds  aimed  at. 

COMMERCIAL   ASPECTS. 

Copper  calculations  were  made,  based  on  a  station  potential 
of  3,000  and  also  of  6,000  volts,  stations  being  50  miles  apart 
(thus  supplying  current  25  miles  on  each  side),  and  on  a  ser- 
vice requiring  one  train  on  each  2 5 -mile  section,  the  drop  on 
the  line  being  33  per  cent,  of  station  potential.  Then,  for  a 
line  of  i  ,000  miles,  as  from  New  York  to  Chicago,  with  copper 
at  15  cents  per  pound,  and  for  3,000  volts  initial  pressure: 

Per  mile. 

Cost  of  conducting  system,  including  frame-work =  $7,000 

station  per  mile,  including  steam  power =     3,000 

double  track,  including  depots,  etc =  55,000 

train  equipment,  3  cars  each,  50  trains  and  engines.. .  .  =     1,000 


Total  per  mile $66,000 

In  this,  the  cost  of  track  construction  is  based  on  road-bed 
figures  reported  for  the  Erie  Railway  Company.  To  arrive 
at  operating  expenses,  suppose  20  trains  each  way  each  day 
and  a  schedule  speed  of  125  miles  per  hour,  i.e.,  8  hours  for 
the  trip.  Suppose  a  station  development  of  800  horse-power 
per  train  on  the  line,  or  6,400  horse-power  hours  per  trip. 
In  stations  of  large  capacity  working  under  the  supposed 
conditions  the  cost  of  one  horse-power  hour  =  0.90  cent, 

20 


3o6  THE    ELECTRIC    RAILWAY. 

or,  per  trip,  for  power,  a  cost  of  $57.60.  For  trainmen,  let 
there  be  two  men  on  each  train  and  one  per  train  in  reserve ; 
and  suppose  $3  per  man  per  trip  of  8  hours,  then,  cost 
per  train  trip  =  3  X  3  =  %>•  Interest  charge  per  train  trip, 
$66,000,000  X  0.05  -r-  365  X  40  =  $225.42.  For  maintenance 
of  way  take  $i  ,000  per  mile  of  double  track  per  annum,  or  per 
day  for  the  supposed  line  $2,700,  or  per  trip,  2,700  -h  40  = 
$67.50.  For  general  expense  of  operating  company,  sup- 
pose $1,000  per  day,  or  per  train  trip  $25.  For  wear  and 
tear,  oil,  etc.,  on  train  itself,  take  $10  per  trip.  Then  total 
=  56.60  -f  9  +  225.42  +  67.50  -f  25  +  10  =  $394-42. 
For  receipts  we  should  have  about  the  following : 
Suppose  the  average  train  be  of  two  cars  (such  as  designed)  t 
having  each  a  capacity  of  about  10,000  pounds  freight  (con- 
sidered to  be  such  as  express  and  mail  matter),  or,  say,  of  15 
passengers.  Suppose  average  train  load  of  freight  15,000 
pounds,  of  passengers  20.  Take  freight  at  33  cents  per  cwt., 
passengers  at  $25.  The  income  per  trip  in  either  case 
$500,  showing  profit  over  fixed  charges  of,  say,  $100  per 
trip,  or  $4,000  per  day.  The  total  daily  load  of  freight, 
each  way,  required  to  justify  the  service  above  treated 
is  300,000  pounds,  or  if  200  through  passengers  be  car- 
ried (i.e.,  10  trains  for  passengers  each  way  each  day),  then 
only  150,000  pounds  of  freight.  The  present  movement 
between  New  York  and  Chicago,  in  mail  and  express,  is  not 
far  from  this  figure.  A  soo-mile  line  connecting  Boston, 
New  York,  Philadelphia,  Baltimore  and  Washington  would 
be  even  more  profitable.  It  is  to  be  remembered  also  that 
a  service  of  small  trains  is  contemplated,  making  fixed  charges 
relatively  very  large.  Much  larger  trains  could  be,  and,  we 
think,  will  be,  run  at  the  speeds  here  considered;  but  we 
believe  that  the  smaller  effort  would  precede  the  larger.  It 
is  further  to  be  noted  that  the  use  of  6,000  volts  potential 
and  the  extension  of  some  existing  roadway  instead  of  the 
building  of  a  new  one  would  diminish  first  cost.  As  grade 
crossings  would  be  out  of  the  question,  and  as  cities  would 
require  to  be  entered  above  or  below  the  surface  (country 
roads  could  be  carried  over  on  bridges) ,  it  is  perhaps  best  to 
consider  only  the  larger  figure  already  used. 


HIGH-SPEED    SERVICE.  307 

To  demonstrate  all,  or  nearly  all,  that  has  been  outlined 
liere  would  cost  about  $300,000,  covering  the  construction  and 
operation  for  a  reasonable  time  of  the  4-mile  circular  line 
proposed  above.  Last  year  the  Baltimore  company  met  un- 
expected difficulty  in  efforts  to  raise  the  needed  money,  and 
their  operations  were  suspended  just  at  the  time  when  plans 
were  completed — even  to  working  drawings. 

Unfamiliar  as  is  the  project,  the  reader  will  perhaps  be  the 
more  ready  to  share  the  confidence  of  its  promoters  on  read- 
ing the  words  from  Prof.  Henry  A.  Rowland  and  Dr.  Louis 
Duncan,  of  Johns  Hopkins  University,  to  whom  were  sub- 
mitted full  details  of  the  plans  partially  described  in  this 
paper.  After  viewing  the  figures  for  power  required,  they 
say: 

"  We  believe  from  the  data  obtained  that  the  values  given 
are  not  too  low,  and  that  the  horse-power  which  Mr.  Crosby 
calculates  is  not  less  than  the  amount  required.  While  we  have 
investigated  carefully  and  considered  all  the  data  obtainable, 
yet  the  existing  experiments  are  not  sufficient  to  accurately 
fix  a  limit  to  the  train  resistance.  We  believe,  however,  that 
the  value  assumed  by  Mr.  Crosby  is  safe. 

"  The  motors,  the  calculations  and  drawings  for  which  are 
in  the  appended  statement,  will  develop  horse-power  for 
which  they  are  designed,  namely,  500  horse-power.  We 
point  out  some  modifications  which  will  be  beneficial.  We 
Relieve  that  they  will  drive  the  train  [locomotive  and  two  cars — 
O.  T.  C.]  at  the  required  speed  [speed  then  considered  being 
120  miles  per  hour  on  a  level]. 

"  The  possibility  of  a  train  being  derailed  by  an  obstruction 
•on  the  track  increases  with  the  speed.  At  speeds  up  to  90 
miles,  however,  there  seems  no  increase  in  the  number  of 
derailments.  In  the  case  in  question  the  center  of  gravity 
of  the  cars  is  very  low,  and  it  would  be  difficult  to  derail  them 
on  straight  parts  of  the  track.  The  radius  of  the  curves  should 
of  course  be  great,  but  not  so  great  as  would  be  required  for 
an  ordinary  train  going  at  these  high  speeds.  The  question 
of  safety  is,  however,  almost  wlwlly  a  question  of  track  construc- 
tion. Considering  the  form  of  the  proposed  train,  its  compar- 
atively light  weight  making  a  less  demand  on  the  track,  it  is 


308  THE    ELECTRIC    RAILWAY. 

certain  that  with  a  carefully  constructed  road  it  could  attain 
with  safety  speeds  which  would  be  impossible  with  trains  as 
at  present  constructed.  As  these  latter  have  several  times 
made  86  miles,  and  often  made  80  miles,  it  would  seem  that  a 
speed  of  120  miles  or  even  more,  with  the  electric  cars,  would  not 
be  outside  the  limits  of  safety. 

"  The  plan  for  supplying  current  to  the  motors  is  feasible. 

"  The  design  of  the  motors  is  discussed  in  the  detailed 
report.  It  is  generally  good. 

"  Should  it  be  demonstrated  by  an  actual  test  that  passenger 
trains  can  be  run  safely  and  economically  at  a  speed  over  IOG 
miles  per  hour  from  here  to  Chicago,  the  financial  aspects 
of  the  case  would  certainly  be  improved.  We  are  of  the  opin- 
ion that  the  chances  are  in  favor  of  this  being  accomplished  by  the 
present  scheme"  (Italics  are  by  the  present  authors.) 

These  words,  though  guarded  and  accompanied  by  criticism 
of  the  detail,  are  yet  a  substantial  approval  of  what  was  sub- 
mitted. 

A  recent  paper  by  Mr.  Carl  Zipernowski,  setting  forth 
plans  (not  yet  well  matured)  for  a  single-car,  125-mile-per- 
hour  passenger  service  between  Vienna  and  Buda-Pesth, 
shows  that  the  interest  in  and  efforts  toward  the  great  step 
soon  to  be  made  are  not  confined  to  the  American  people — 
usually  more  adventurous  (though  perhaps  less  thorough- 
going) than  their  European  cousins.* 

*  Since  the  first  edition  of  this  work  a  very  notable  contract  has  been  entered  into  be- 
tween the  Baltimore  and  Ohio  Railway  Company  and  the  General  Electric  Company. 
This  contract  calls  for  the  construction  of  three  8o-ton  electric  locomotives  capable  of 
doing  service  as  follows  :  To  pull  a  i2oo-ton  train  at  15  miles  per  hour  over  an  6.8  per  cent 
grade,  and  to  pull  a  soo-ton  train  over  the  same  grade  at  a  speed  of  30  miles  per  hour. 
The  locomotives  are  to  operate  in  a  tunnel  about  three  miles  long,  which  the  Baltimore 
&  Ohio  Railway  Company  has  built  through  and  under  the  city  of  Baltimore,  Md. 

The  locomotive  will  probably  be  constructed  to  permit  of  much  higher  speed  with 
lighter  loads,  those  mentioned  being  maximum  for  the  freight  and  passenger  service, 
respectively,  which  are  contemplated  as  possible  within  the  next  ten  years.  It  is  ex- 
pected that  these  locomotives,  which  will  be  driven  by  direct-coupled  slow-speed  genera- 
tors, will  be  in  operation  in  the  summer  of  1893. 

The  confidence  thus  shown  by  two  large  companies  in  the  future  of  electric  traction 
on  a  large  scale  is  most  reassuring  to  those  who  follow  the  progress  of  the  art. 


CHAPTER   XI. 

COMMERCIAL   CONSIDERATIONS. 

IN  treating  of  the  commercial  value  of  any  enterprise  we 
are  led  to  discuss: 

1.  Original  investment. 

2.  Cost  of  maintenance  and  operation. 

3.  Gross  income. 

Of  the  original  investment  required  for  a  street  railway  the 
two  most  important  items  are  those  to  which  it  is  most  diffi- 
cult to  assign  average  values  that  may  serve  as  useful  guides. 
These  two  items  are  cost  of  franchise  and  cost  of  track  con- 
struction. It  may  be  said  that  the  franchise  may  cost 
from  $0.00  to  $500,000  per  mile  of  roadway.  Track  con- 
struction may  run  from  $5,000  to  $50,000  per  mile  of  single 
track. 

It  should  be  added,  however,  that  variation  in  this  item  is 
often  due  to  the  fact  that  it  is  made  to  bear  a  part  of  the 
charge  for  franchise,  imposed  in  the  shape  of  restrictions  as 
to  the  how  or  where  of  performing  the  necessary  engineering 
work.  In  treating  the  matter  here  we  shall  omit  considera- 
tion of  the  franchise  cost,  and  give  moderate  values  for  track 
construction,  not  applicable  where  special  engineering  diffi- 
culties are  to  be  met. 

The  minimum  figure  above  given — $5,000  per  mile  of 
single  track — cannot  often  be  reached.  It  supposes  a  45- 
pound  T-rail,  cross-tie  work,  with  very  light  grading  and  no 
paving. 

In  the  general  summary  of  cost  intended  here  to  be  pre- 
sented we  shall  take  $10,000  per  mile  of  single  track  as  a 
safe  average  figure.  This  estimate,  however,  is  not  designed 
to  cover  the  expense  required  to  make  of  the  track  a  good 
conductor.  Let  us  suppose  for  this  purpose  a  No.  o  bare 
copper  wire  to  be  laid  and  bonded  to  each  rail,  as  described  in 

309 


3IO  THE   ELECTRIC    RAILWAY. 

"  Instructions  to  Linemen"  (see  Appendix  B).  For  this  item 
it  is  safe  to  estimate  $200,  covering  labor,  and  $400  for  ma- 
terial. 

Going  next  to  the  poles,  a  fair  figure  for  round,  trimmed 
cedar  poles,  laid  down,  not  set,  may  be  taken  at  $2.50. 
Squared  poles  of  Georgia  pine  maybe  had  for  $3.50;  and 
in  either  case  setting,  if  without  concrete  or  blasting,  need 
not  cost  more  than  §2  to  $2.50.  For  a  good  sawed  pole, 
with  one  cross-arm,  it  is  safe  to  say  that  $600  per  mile 
will  cover  the  cost,  the  cross-suspension  method  being  sup- 
posed. (As  the  poles  are  set  about  125  feet  apart,  longitu- 
dinally, and  one  on  each  side  of  the  street,  we  count  on 
about  90  poles  per  mile.) 

Iron  poles  may  be  had  for  from  $18  to  $27  each.  The 
pole  of  lower  cost  will  stand  ordinary  strains.  At  curves 
or  other  special  points  something  heavier  may  be  required. 
The  standard  round  pole,  in  three  sections,  of  6,  5,  and  4  inch 
diameter,  respectively,  may  be  had  for  about  $22.  Setting 
of  these  poles  in  concrete,  without  blasting,  should  not  cost 
more  than  $5  each.  Blasting  alone  may  cost  from  $10  to 
$20  per  pole.  For  a  mile  of  iron  poles  (90),  set,  we  take 
$2,500  as  a  fair  figure. 

They  will  last  longer  than  wood,  look  somewhat  better 
than  the  best  sawed  pole,  but  are  less  desirable  in  one  re- 
spect, namely,  that  the  liability  to  "grounds"  is  somewhat 
greater  than  with  wooden  poles. 

The  bare  trolley  wire  will  cost  from  $175  to  $285  per  mile, 
according  to  size — the  latter  figure  covering  No.  o  B.  & 
S..  at  present  market  rates.  Cost  of  span  wire,  insulators, 
etc.,  maybe  taken  at  about  $100  per  mile;  labor  of  erect- 
ing wires,  superintendence  of  contingencies,  at  about  $325 
per  mile.  Taking  $275  for  the  cost  of  the  bare  trolley 
wire,  we  have  $700  per  mile,  covering  the  trolley  wire  in 
place. 

The  amount  of  feed  wire,  of  course,  is  indefinite,  as  has 
been  explained  in  Chapter  IV. 

The  following  costs  per  mile  of  a  good  insulated  wire  show 
how  the  amount  may  be  made  up,  having  determined  the 
length  and  cross-section  of  feeders: 


COMMERCIAL   CONSIDERATIONS.  311 

No.  o  B.  &  S.  per  mile $500 

No.  oo  B.  &  vS.  per  mile 650 

No.  ooo  B.  &  S.  per  mile 850 

No.  oooo  B.  &  S.  per  mile 975 

The  cost  of  erecting  this  wire  runs  from  $75  to  $100  per 
mile.  As  a  safe  general  figure  we  may  take  $1,000,  cover- 
ing feeder  wire  in  place.  Resuming,  we  have: 

Track  construction $10,000 

Earth  circuit 600 

Wooden  poles 600 

Trolley  wire,  etc 700 

Feed  wires. .  1,000 


Total,  track  and  line,  per  mile $12,900 

If  iron  poles  be  used,  add  $2,000,  or,  in  round  figures, 
say  $13,000  with  wooden  poles,  $15,000  with  iron  poles. 

Car  bodies,  ready  for  motors,  may  be  had  for  from  $750  to 
$1,500,  the  higher  figure  referring  to  those  of  unusual  con- 
struction. A  very  good  body  may  be  had  for  $1,000,  for 
a  1 6-foot  car.  The  longer  bodies  cost  from  $1,250  to 
$2,000  each.  Trucks  for  these  cost  about  $600.  Electri- 
cal equipment,  consisting  of  two  15 -horse-power  motors 
and  accessories,  may  be  taken  at  from  $1,800  to  $2,500, 
according  to  the  make.  If  one  motor  be  used,  from  $1,100 
to  $1,800.  Assuming  $2,250  for  the  electrical  equipment, 
the  car  ready  to  operate  costs  $3,500.  (All  the  figures 
here  and  elsewhere  used  suppose  goods  are  purchased  for 
cash.  No  treatment  can  here  be  given  to  the  increase  of 
figures  due  to  various  forms  of  credit.) 

Passing  now  to  the  station,  it  is  to  be  noted  that  the  cost 
per  horse-power  of  the  steam  and  electric  plant  varies  con- 
siderably with  the  size  of  the  installation.  For  convenience 
here,  let  us  suppose  the  steam  and  the  electric  plant  to  be 
each  of  500  horse-power  capacity.  We  may  then  assume, 
per  horse-power  installed,  for  a  complete  high-speed  steam 
plant,  including  boilers  and  fittings,  $50* — for  a  complete 

*  For  a  low-speed  steam  plant  *hese  figures  should  be  somewhat  increased— say  20  per 
cent. 


2J2  THE    ELECTRIC    RAILWAY. 

electric  plant,  $40,  or  $90  per  horse-power  for  the  combi- 
nation. It  has  been  shown  that  there  should  be  provided 
from  10  to  20  horse-power  at  the  station  for  each  car  on  the 
line.  Taking  15  horse-power  per  car,  it  appears  that  an 
investment  of  $1,350  must  be  made  in  station  machinery  per 
car  to  be  operated. 

The  cost  of  ground  space  for  station,  car-barn  and  office 
will,  of  course,  vary  widely.  The  cost  of  buildings  will  also 
vary  considerably,  there  being  in  this  item  a  considerable 
"personal  equation"  of  the  particular  management.  Since 
we  desire  to  present  some  reasonable  figure,  we  find  that 
$50  per  horse-power  of  station  capacity  may  serve  in  a 
majority  of  cases  to  cover  all  real  estate.  Reduced  to  the 
investment  per  car  to  be  operated,  this  becomes  $750.  If, 
now,  there  were  any  fixed  number  of  cars  per  mile  of  track 
or  mile  of  street,  the  whole  investment  might  be  expressed 
at  a  certain  amount  per  car  operated.  This  ratio,  however, 
varies  widely — being  principally  determined  by  the  size  of 
the  city  in  question. 

It  may  be  roughly  stated  that  cities  of  population  from 
15,000  to  100,000  show  from  one  to  two  cars  per  mile  of  track, 
while  from  100,000  to  300,000  inhabitants  there  should  be 
from  two  to  four  cars  per  mile. 

So,  in  still  larger  cities,  a  slightly  higher  ratio. * 

Let  us  take  two  cases — first,  that  in  which  we  find  one  car 
per  mile  of  track.  The  investment  per  1 6-foot  car  then 
becomes: 

One  mile  track  and  line,  wooden  poles $13,000 

One  car  ready  to  run 3, 500 

Steam  and  electric  plant  per  car i,35o 

Real  estate. .  .  .  700 


Total,  per  car $18,550 

Then,  second,  for  three  cars  per  mile,  iron  poles  on  line, 
the  items  are  as  above,   except  track  and  line,  which  now 

*  The  West  End  Company  of  Boston  serves  about  650,000  people.      It   has  260  miles    of 
track  and  2,745  cars.     New  York  City  has  276  miles  of  track  and  2,519  cars. 


COMMERCIAL   CONSIDERATIONS.  313 

enter  at  $5,000  (one-third  of  $15,000)  per  car,  or  the  total 
per  car  $10,550. 

We  may  now  find  the  interest  charge  per  car-mile,  which 
is  a  convenient — perhaps  the  most  convenient — unit  of  oper- 
ating- expense  and  earning  capacity. 

Each  car  may  be  taken  to  make  35,000  miles  per  year — a 
little  less  than  a  steady  average  of  100  miles  per  day,  for  all 
cars. 

At  5  per  cent,  on  $18,550  we  have  per  annum.  .  $927.50 
or,  per  car-mile,  2.65  cents.  . 

At  5  per  cent,  on  $10,550  we  have  per  annum.  .      527.50 
or,  per  car  mile,  1.5  cents. 

Thus  far  the  reports  of  operating  expenses  of  electric  rail- 
ways 'have  been  widely  divergent.  Some  order  is  now 
beginning  to  appear.  It  should  be  recognized,  however, 
that  considerable  differences  as  between  one  company  and 
another  must  continue  to  exist  until  local  prices  of  labor  and 
material  shall  be  everywhere  uniform.  We  have  seen  many 
useless  contentions  as  to  the  proper  average  figure  for  oper- 
ating expenses,  one  contestant  having  in  mind  labor  of 
motor-men  and  conductors  at  22  cents  per  hour,  as  in  Boston, 
Mass.,  the  other  considering  the  same  item  at  11  cents  per 
hour,  as  in  Knoxville,  Tenn.,  and  very  many  other  cities  of 
comparatively  small  population. 

So,  the  one  has  in  mind  coal  at  about  $5  per  ton,  as  in 
Boston,  the  other  coal  at  about  $1.75,  as  in  Knoxville. 

Again,  one  may  consider  a  road  of  5  or  6  cars  which  runs 
its  own  independent  station  at  a  necessarily  high  figure  per 
car,  while  another  refers  to  a  similar  small  road  that  may 
have  its  dynamos  in  an  electric-light  station,  an  equitable 
arrangement  being  made  for  the  additional  coal  and  wear 
and  tear — the  additional  attendance  and  general  expense 
being  almost  nil. 

Let  us  take  up  the  various  parts  of  operating  expense, 
seriatim. 

As  to  the  cost  of  getting  upon  the  line  the  electric  power 
needed  for  one  car -mile  of  ivork,  it  could  be,  in  a  station  of 
about  500  horse-power  capacity,  not  far  from  i.o  to  1.2  cents, 
as  shown  by  Table  III.,  Chapter  X.  (i.e.,  table  of  cost  of  one 


3I4  THE    ELECTRIC    RAILWAY. 

horse-power  hour  in  various  stations).  The  cost  per  horse- 
power hour  is  a  little  more  than  this  figure,  since  one  horse- 
power hour  will  produce  a  little  more  than  one  car-mile  of 
service,  say  1.2  miles.  For  long  cars  the  figures  should  be 
increased  by  at  least  50  per  cent. ;  we  would  then  have  a 
station  cost  of  1.5  to  1.8  cents. 

These  figures,  too,  may  hold  for -a  standard  1 6-foot  car 
drawing  a  trailer.  In  the  figures  here  given,  taken  from  the 
table,  coal  enters  at  0.475  cent  Per  horse-power  hour.  It  is 
assumed  to  cost  $3  per  ton  and  to  be  burned  at  the  rate  of 
3.2  pounds  per  horse-power  hour. 

As  a  matter  of  fact,  the  consumption  per  horse-power  hour 
generally  goes  far  beyond  this.  Bad  design  of  station,  as  in 
wrong  relation  between  capacity  and  service  of  engines,  poor 
piping,  etc.,  together  with  poor  firing,  may  double,  even 
treble,  this  figure.  We  must,  therefore,  be  understood  as 
speaking  of  what  can  be  done  by  good  practice,  not  of  what  is 
done  by  bad  practice.  The  effect  upon  the  cost  per  car-mile, 
should  coal  consumption  be  trebled,  would  be  to  add  about 
0.8  cent,  making  nearer  to  2.0  than  i.o  as  the  round  figure. 
We  have  seen  reports  of  less  actual  cost  than  that  resulting 
from  the  table  and  mentioned  above.  But  in  a  majority  of 
cases  actual  practice  is  worse  than  the  tabular  figure.  We  have 
therefore  averaged  several  cases  of  practice  generally  called 
good,  and  find  1.35  as  a  fair  figure.  Many  statistics  show 
higher.  * 

The  difference  between  maximum  and  minimum  values  is 
striking.  But  it  should  be  noticed  that,  in  the  average,  roads 
operating  3  cars  are  grouped  with  those  operating  140.  In 
many  respects,  but  especially  in  the  cost  of  power,  must  there 
be  very  wide  differences  between  very  small  and  very  large 
plants.  It  scarcely  seems  useful  to  average  results  obtained 

*  Mr.  J.  S.  Badger  (Tiie  Electrical  World,  October  30,  1891)  reports  as  the  average  of 
twenty-two  trolley  roads  a  cost  of  2.32  cents  for  this  item.     It  is  made  up  as  follows. 
Maintenance  of  power  plant,  repairs  on  engines,  dynamos,  etc. 
Highest.  Lowest.  Average. 

°-86  0.05  0.36 

Fuel,  wages,  oil,  waste,  etc.,  at  station. 
Highest.  Lowest.  Average. 

4-95  0.48  i.Q6' 

These  two  items  should  be  summed  to  get  cost  of  power  in  the  line,  making  0.36  -f  1.96  = 


COMMERCIAL   CONSIDERATIONS.  315 

under  such  widely  different  conditions.  The  figures  given 
in  the  text  are  not  expected  to  apply  to  very  small  plants. 
They  will  be  useful  as  applied  to  companies  operating,  say,  10 
cars  or  more.  See  curves  (page  286)  showing  change  in  cost 
of  one  horse-power  hour  according  to  change  in  magnitude  of 
station.  The  change  up  to  about  500  horse-power  is  very 
rapid. 

As  an  example  of  good  station  service  the  East  Harrisburg 
Street  Railway  Company  may  be  cited.  They  kindly  report 
to  us  as  follows: 

POWER  PLANT  EXPENSE  FOR  MONTH  SEPTEMBER,    189!. 

Coal  at  $2 .  i  o  per  ton $24 1.12 

Dynamo  oil . 5.55 

Cylinder  oil 5.80 

Waste  and  coal  oil 3.81 

Engineer  and  fireman 206.63 

Sundries 21.24 


Total $484. 1 5 

Number  of  cars,  18;  mileage,  63,028.  Cost  per  car-mile, 
0.75  cent. 

Many  contracts  heretofore  made  between  lighting  com- 
panies and  railway  companies  have  been  on  a  car-day  basis, 
with  some  expressed  or  implied  assumption  concerning  car- 
miles  per  day.  Unless  the  parties  to  such  contracts  are  sat- 
isfied to  let  matters  rest  on  a  guesswork  basis,  it  is  certainly 
best  to  at  least  come  as  near  to  the  facts  as  possible  by  the 
car-mile  unit.  The  most  accurate  guide  for  proper  charge  is 
to  be  found  in  watt  readings  taken  at  the  station,  all  the 
peculiarities  of  service  (pro  and  cou  the  railway  company) 
being  thus  taken  into  account. 

When  it  is  remembered  that  occasional  line  leaks  have  been 
found — in  one  case  reaching  a  flow  of  60  amperes — the  wis- 
dom of  this  course  will  be  better  appreciated.  True,  there 
are  as  yet  no  satisfactory  large  wattmeters  for  railway  sta- 
tions: but  several  small  ones  may  be  used  in  multiple,  or 
frequent  reading  of  the  ammeters  (checked  by  frequent 


316  THE   ELECTRIC    RAILWAY. 

reading  of  the  voltmeter)  will  generally  give  a  closer  deter- 
mination than  can  be  made  by  estimating  the  consumption 
per  car-day,  or  even  per  car-mile. 

In  case  a  contract  of  this  sort  is  about  to  be  made  we  would 
advise  the  following  course :  Agree  upon  a  rate  per  horse- 
power hour,  a  minimum  of  consumption  being  fixed,  or  on  a 
sliding  scale  with  respect  to  amount  of  power  used ;  have 
five-minute  readings  on  the  ammeter,  and  fifteen-minute 
readings  on  the  voltmeter  taken  during  a  period  of,  say,  four 
weeks ;  keep  a  close  record  of  the  car-miles  made  during  the 
same  period. 

In  this  way  a  very  reliable  figure  for  power  per  car-mile 
can  be  had,  and  the  frequent  readings  may  be  discontinued — 
to  be  taken  up  again  when  the  season  changes,  as  from  sum- 
mer to  winter,  and  to  be  occasionally  renewed  as  a  check  on 
any  changes  in  service.  As  soon  as  reliable  recording  watt- 
meters can  be  had  for  all  stations  there  need  be  no  more 
uncertainty  in  a  contract  of  this  sort  than  is  the  case  in  a 
contract  for  the  supply  of  gas  to  a  building. 

Some  existing  contracts  call  for  a  certain  sum  per  day  for 
each  generator  of  a  given  size  that  may  be  in  operation. 
This  method  is  of  course  less  accurate  than  the  others.  A 
just  relation  between  service  and  cost  may  be  hit  upon  and  it 
may  not. 

For  a  small  number  of  cars,  say  six,  it  is  not  uneconomical 
to  pay  4  cents  per  car-mile  rather  than  erect  a  suitable  sta- 
tion. There  will  not  be  a  great  profit  in  this  to  the  lighting 
company  unless  they  have  already  all-day  attendance  as  a 
part  of  the  lighting  service.  Four  cents  per  horse-power 
hour  or  per  car-mile  leaves  a  handsome  percentage  of  profit 
to  the  power  station,  and  yet  the  railway  company  can  scarcely 
compete  with  that  figure  by  their  independent  production  on 
a  very  small  scale. 

In  the  matter  of  motor  repairs  the  advances  of  the  current 
year  will  make  a  great  and  welcome  change.  There  has 
been  a  wide  variation  in  the  experiences  of  different  com- 
panies; averages  have  been  less  useful  guides  than- will  now 
be  the  case.  Perhaps  the  widest  fluctuation  of  "luck"  has 
been  found  in  connection  with  armature  repairs ;  next  would 


COMMERCIAL   CONSIDERATIONS.  317 

follow  field  windings.  It  is  safe  to  say  that  ten  roads  might 
be  chosen  from  which,  selecting  two  sets  of  five  each,  the 
average  armature  and  field  repair  account  for  the  one  set 
would  be  five  times  that  of  the  other.  Individual  instances 
may  be  found  in  which  one  road  has  had  five  times  as  much 
intelligence  in  its  management  as  a.  neighboring  road,  and 
may  have  had  armatures  made  with  five  times  or  with  one- 
fifth  of  the  care  given  to  those  that  chanced  to  be  received 
by  that  neighbor. 

The  winding  of  electrical  apparatus  is  largely  a  matter  of 
conscience  as  well  as  skill.  Constant  supervision  cannot  be 
given  to  every  workman,  yet  a  moment  of  negligence  or  ill- 
will  on  his  part  may  fatally  weaken  an  armature.  Shop- 
testing  is  important — should  never  be  omitted ;  yet  it  cannot 
bring  out  all  weaknesses  as  they  are  brought  out  by  bad 
handling  on  the  road,  or  even  by  the  exigencies  of  legitimate 
service.  In  all  this  matter  the  most  marked  improvement 
recently  made  is  the  use  of  Gramme  or  hollow-cylinder  arma- 
tures instead  of  Siemens  or  solid-core  armatures. 

Field  windings  have  been  much  improved  by  good  detail 
work  and  by  decreasing  the  heat  developed  in  them,  or 
increasing  the  rate  of  dissipation  of  that  heat.  In  gears, 
too,  there  has  been  a  great  change  for  the  better.  The 
number  has  been  diminished,  the  speed  reduced,  and  those 
that  remain  have  been  carefully  inclosed  in  dust-proof  cas- 
ings. These,  besides  excluding  dust,  pebbles,  etc.,  serve  also 
as  reservoirs  for  oil  or  grease,  into  which  the  larger  gear 
(axle  gear)  dips  half  an  inch  or  more,  thus  lubricating  itself 
and  the  armature  pinion.  Experience  with  these  improved 
forms  has  not  been  extended  enough  to  show  accurately  what 
their  repair  rate  is ;  but  that  it  will  be  greatly  less  than  that 
of  the  earlier  high-speed,  exposed  motors,  we  have  priina 
facie  evidence  of  the  strongest  character,  and  also  the  grati- 
fying results  of  some  months  of  practical  use  for  some  hun- 
dreds of  such  motors  as  are  here  described. 

The  following  table,  based  on  the  returns  of  several 
millions  of  car-miles  of  hard  work  under  good  management, 
shows  the  life  of  various  wearing  parts  in  double-reduction 
motors.  These  machines  were  covered  on  the  side,  rather 


2!g  THE   ELECTRIC    RAILWAY. 

loosely,  by  canvas,  and  under  the  bottom  a  metal  pan  was 
hung.  Dust  was  not  excluded,  but  the  protection  from  peb- 
bles, etc.,  was  good. 

Life  in  Firct  rr>=f          Cost  per  car- 

Article,  car-miles.  First  cost.         miie  in  cents. 

Axle  gear 29,600  $7.50  0.025 

Intermediate  gear 28,600  6.25  0.022 

Intermediate  pinion 10,050  6.75  0.067 

Armature  pinion 8,260  6.05  0.073 

Trolley  wheel 5-75°  i-4°  0-025 

Armature  bearing 24,200  3.70  0.015 

Intermediate  bearing 35, 100  4.40  0.013 

Total 0.240 

It  may  be  said  that  many  roads  have  shown  a  repair  account 
for  motors,  gears  and  trolleys  running  from  2  to  3  cents  per 
car-mile — some  even  higher.  We  can  see  no  reason  why, 
with  slow-speed  machinery,  this  item  need  go  beyond  i  cent. 
It  can  be  shown  to  be  considerably  less  than  this  for  the 
period  during  which  the  single-reduction  motors  have  been 
in  use. 

Maintenance  of  the  line  is  well  covered  by  5  per  cent,  on 
its  cost.  Averaging  this  in  iron  and  wooden  pole  construc- 
tion, at  $3,000  per  car  for  line  investment  and  at  35,000 
car-miles  per  year  per  car,  this  item  amounts  to  0.4  cent 
per  car-mile.  At  $1,000  line  investment  per  car  it  becomes 
0.14  cent.  It  is  an  interesting  fact  that  on  curves,  where 
traffic  is  very  dense,  the  sides  of  the  trolley  wire  are  worn  by 
the  trolley  flanges  so  as  to  require  renewal  of  the  wire  in  a 
very  few  years. 

Maintenance  of  dynamos  and  engines  has  already  been 
accounted  for  in  taking  the  cost  of  power  from  the  table. 

Maintenance  of  track  for  electric  railways  is  still  a  some- 
what uncertain  factor.  Typical,  well-constructed  electric 
railway  road-beds  are  not  numerous;  use  of  them  has  not 
been  long;  reports  have  not  been  full;  paving  expenses 
(varying  widely  according  to  municipal  requirements)  have 
been  combined  with  those  of  the  track  proper. 

It  is  found  that  OQ  steam  railways  the  injury  to  track  is 
approximately  in  proportion  to  the  number  of  locomotive 
miles,  rather  than  total  ton-miles,  including  train  weights. 
In  other  words,  each  passage  of  a  set  of  driving  wheels  does 


COMMERCIAL   CONSIDERATIONS.  319 

a  certain  amount  of  injury,  and  this  amount  is  great  in  com- 
parison to  that  done  by  the  car  wheels  following.  In  street 
railway  practice  car-miles  and  driving-wheel  miles  are  almost 
always  as  i  to  2  (or  i  to  4),  since,  except  for  trailer  service 
(rarely  exceeding  two  trailers) ,  locomotive  and  carrying  car 
are  combined.  The  West  End  Street  Railway  Company  of 
Boston,  Mass.,  operating  about  325  electric  cars  over  tracks 
not  yet  completely  relaid  for  electric  services,  reports  the 
track  maintenance  at  i.oS  cents  per  car-mile.  The  same  fig- 
ure is  reported  by  the  Pleasant  Valley  Railway  Company,  of 
Pittsburg,  Pa.*  Until  more  extended  figures  can  be  obtained 
we  may  adopt  these  as  a  fair  guide.  No  distinction  is  here 
made  between  effect  of  long  cars  and  sho'rt  cars,  though  the 
former  are  in  considerable  number  on  the  West  End  lines. 

Maintenance  of  car  bodies  and  trucks  is  thoroughly  covered 
by  allowing  20  per  cent,  per  annum  on  their  cost,  i.e.,  $250, 
or  0.72  cent  per  car-mile. 

We  have  already  stated  that  in  the  matter  of  wages  of  con- 
ductors and  motor-men  wide  differences  are  to  be  found. 
The  pay  per  hour  is  known  to  vary  from  10  cents  to  22  cents. 
Let  us  take  18  cents  as  an  average.  We  then  have  36  cents 
for  the  two  men.  They  will  run  very  nearly  8  miles  per 
hour  while  under  pay ,  hence  the  cost  per  car-mile  is  4. 5  cents. 

On  a  few  electric  roads,  in  rather  small  cities,  no  conductors 
are  employed.  Even  with  horse  cars,  however,  it  has  been 
found  of  advantage  to  have  conductors  in  nearly  all  towns  of 
considerable  size.  Of  cities  in  the  United  States  having 
more  than  100,000  inhabitants  we  now  recall  only  one,  New 
Orleans  (population  242,000),  in  which  conductors  are  not 
employed.  The  higher  speed  made,  the  greater  number  of 
passengers  carried,  and  the  occasional  attention  required  for 
the  trolley  are  all  considerations  which  give  greater  value  to 
the  conductor  on  an  electric  than  on  a  horse  car. 

*  Rather  curiously,  just  half  of  this  amount  is  reported  by  Mr.  J.  S  Badger  ( The  Electrical 
World,  Oct.  30,  1891)  as  the  average  given  by  twenty-two  trolley  roads  for  maintenance  of 
way.  The  highest  figure  given  in  the  averages  is  1.86  cents,  the  lowest  o.  10  cent.  Prob- 
ably reconstruction  of  old  track  will  in  part  explain  the  very  high  figure;  use  of  perfectly 
new  track  for  a  short  time  probably  explains  the  very  low  figure.  Mr.  Badger's  report 
appeared  after  the  text  above  was  written,  and  is  a  valuable  contribution  to  our  knowl- 
edge of  the  actual  operating  expense.  In  this  particular  item,  however,  we  think  it  safer 
to  adhere  to  the  larger  figure,  1.08,  reported  by  companies  operating  a  considerable 
mileage  for  a  consi.'lc-rablo  *-ime. 


220  THE   ELECTRIC    RAILWAY. 

The  charge  for  accidents  is  another  widely  varying  item 
On  the  same  road  it  varies  much  from  month  to  month,  or 
from  season  to  season.  From  an  examination  of  a  number 
of  cases  we  find  that  0.25  cent  per  car-mile  is  not  far  from  a 
fair  average.  Insurance  companies  have  recently  placed 
accident  risks  for  a  number  of  electric  railway  companies, 
generally  for  a  fixed  percentage  of  gross  receipts.  This  per- 
centage has  varied  from  0.75  of  i  per  cent,  to  2.25  per  cent., 
the  higher  figure  in  cities  having  a  bad  accident  record,  due 
to  unusually  crowded  streets.  To  show  the  relation  existing 
between  the  figure  just  assumed  and  those  held  in  view  by 
the  insurance  companies — a  certain  railway  company  has 
gross  receipts  of  about  20  cents  per  car-mile.  Its  rate  is  i 
per  cent,  (very  nearly).  This  means  0.20 cent  per  car-mile, 
a  little  less  than  the  figure  assumed.  Three  months'  average 
— April,  May  and  June,  1891 — for  this  item  on  the  West 
End  Railway  Company  of  Boston  shows  .57  cent  per  car-mile. 
Mr.  Badger,  in  the  report  referred  to  in  the  last  foot-note, 
takes  0.06 1  cent.  This  seems  entirely  too  low. 

General  expense,  covering  officers'  salaries,  office  expenses, 
superintendent,  taxes,  insurance,  etc.,  runs  from  i.o  to  2.25 
cents  per  car-mile.  In  making  general  estimates  it  is  best 
to  take  at  least  2.0  cents. 

Resuming,  the  various  items  for  an  average  case  appears 
thus: 

COST    PER   CAR-MILE    (STANDARD    1 6-FOOT    CAR). 

Power  delivered  on  line 1.35  cents. 

Repairs  on  electric  machinery  of  car  i.oo  " 

Repairs  on  line 0.43  " 

Conductors  and  motor-men 4. 50  " 

Repairs  on  cars  and  trucks o.  72  " 

Maintenance  of  roadway i  .08  " 

General  expense 2.00  " 

Accidents 0.25  " 


Total 


11.33  cents. 


Throughout  the  above  calculation  good  management  is  sup- 
posed. 


COMMERCIAL   CONSIDERATIONS.  321 

An  inspection  of  these  items  shows  the  great  advantage  to 
be  attained  from  running  trail  cars  whenever  their  use  is 
justified  by  the  traffic.  The  consumption  of  power  for  the 
two  cars  will  not  exceed  50  per  cent,  of  that  required  for  the 
motor  car  alone,  since  all  losses  of  transmission  are  met  in 
the  former.  One  active  conductor  will  take  care  of  both 
cars.  Maintenance  of  line,  of  track,  and  of  car  machinery 
are  scarcely  increased  at  all.  Nor  does  it  appear  that  gen- 
eral expense  would  be  considerably  increased.  Assuming, 
however,  that  this  item  must  always  be  in  proportion  to  the 
volume  of  business  done,  we  have  still,  on  the  above  basis 
for  a  motor  car,  not  more  than,  say,  5  or  6  cents  for  the  cost 
Cx  running  a  trail  car-mile. 

Comparing  the  cost  of  operating  a  two-car  train  (motor  car 
and  one  trailer)  with  that  for  one  long  double-truck  car,  it 
would  appear  that  they  are  very  nearly  the  same.  Service 
based  on  the  long  car  is,  however,  much  less  elastic  in  meet- 
ing traffic  demand  than  is  that  based  on  the  use  of  trailers. 
The  additional  expense  over  that  for  the  standard  car  must 
be  met  at  all  times,  whether  traffic  be  heavy  or  light.  More 
tim  >  is  required  to  take  on  and  let  off  passengers  from  the 
long  car  than  from  the  two  shorter  ones,  or  even  from  a 
single  standard  car  carrying  the  same  load  as  the  long  car. 

Let  us  see  approximately  what  it  costs  to  stop  a  car,  without 
now  considering  the  loss  of  schedule  speed  (or  the  greater 
consumption  of  current,  if  speed  be  maintained)  due  to  in- 
crease of  time  for  stops.  For  convenience,  take  the  even 
figures  12  cents  and  16  cents  as  the  cost  per  car-mile  for 
short  and  long  cars  respectively.  At  9  miles  per  hour, 
schedule  speed,  we  have  the  cost  per  hour  of  running  equal  to 
1 08  and  144  cents  respectively.  This,  per  minute,  equals  1.8 
cents  and  2.4  cents  respectively.  Suppose  the  average  time 
lost  per  stop,  from  full  speed  to  full  speed  again,  be  10  sec- 
onds and  15  seconds,  respectively,  for  short  and  for  long  cars. 
These  figures  correspond  very  nearly  to  the  observed  facts 
in  several  cases.  Then  for  cost  of  a  short-car  stop  we  have 
1.8  -7-  6  =  0.3,  for  a  long-car  stop  2.4  -=-  4  =  0.6  cent,  or  just 
twice  as  great. 

The  advantage  of  the  long  car  over  the  motor  car  and 


322  THE    ELECTRIC    RAILWAY. 

trailer  lies  in  its  smoother  motion  over  the  track.  How  far 
this  will  enter  as  an  earning  factor  it  is  difficult  to  say.  We 
know  that  improvement,  the  refinement  of  service,  generally 
carries  with  it  increase  of  travel.  The  pedestrian,  seeing  a 
chance  to  get  a  seat,  enters  the  car  which,  if  already  crowded, 
he  would  not  have  entered.  High  speed,  carpeted  seats, 
good  lights,  nice  trimmings,  general  neatness,  politeness  of 
employees— all  these  increase  the  number  of  passengers. 
And  all  these  may  be  given,  together  with  greater  ease  in 
entry  and  exit,  in  the  motor  and  trail  car.  Whether  the 
smooth  riding  of  the  double  truck  will  attract  additional  pas- 
sengers, only  a  long  experience  can  determine.*  At  present 
there  is  a  reaction  toward  the  trail  car. 

As  to  how  far  it  is  best  to  go  in  furnishing  seating  capacity,, 
there  are,  indeed,  certain  conditions  of  heavy  travel — as  when 
every  standard  1 6-foot  car  that  can  be  run  shows  standing 
crowds — for  which  it  is  plain  that  either  the  long  car  or  the 
train  must  be  applied.  For  traffic  less  than  this,  yet  quite 
heavy  for  the  single  car,  and  which  might  be  increased  by' 
further  comfort  in  riding,  we  can  only  say  that  each  partic- 
ular case  must  be  determined  by  trial  and  good  judgment. 

Passing  now  generally  to  the  question  of  earnings,  we  can. 
do  little  more  than  refer  to  the  facts  as  disclosed  by  reports. 
It  is  evident  from  the  figures  above  given  how  much  must 
be  earned  in  order  that  the  enterprise  may  be  self-supporting. 
We  may  say  roughly  that  an  electric  car  must  earn  1 5  cents 
gross  per  mile  run  in  order  to  pay  5  per  cent,  on  the  invest- 
ment— no  account  being  taken  of  cost  of  franchise.  In  large 
cities,  where  labor  is  considerably  higher,  this  figure  must 
be  increased  to  18  or  20  cents. 

Since,  in  the  United  States,  the  fare  is  almost  everywhere 
the  same — 5  cents — it  follows  that  for  every  mile  run  the 
company  should  receive  from  three  to  four  passengers  in 
order  to  live.  Expressed  in  passengers  per  car  per  day,  as- 
suming 1 10  miles  per  day  as  made  by  each  car,  the  required 
numbers  are  from  330  to  440.  The  relation  between  the 

*  The  question  of  side  entrances  for  these  long  cars  is  now  considered  as  a  serious  one 
by  all  the  companies  who  have  had  any  experience  in  their  use.  A  recent  double-decked 
long  car,  manufactured  by  the  Pullman  Company,  of  Pullman,  111.,  shows  both  side  and 
end  entrances. 


COMMERCIAL    CONSIDERATIONS. 


323 


population  of  a  city  and  the  total  number  of  people  who  ride 
in  street  cars  is  an  interesting  inquiry.  It  is  also  full  of 
irregularities.  The  "lay"  of  the  city,  the  occupation  and 
habits  of  its  inhabitants,  the  quality  of  the  service  given,  are 
all  of  great  value  in  determining  the  number  of  fares  to  be 
taken  from  a  given  number  of  people.  This  ratio  is  fre- 
quently expressed  in  this  way — that  the  whole  population  is 
carried  so  many  times  per  year  or  per  day.  On  pages  324 
.and  325  we  give  a  table  setting  forth  important  commercial 


c 

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POPULATION   OF   CITIES   BY  THOUSANDS 
FIG.    126. 

facts  of  the  street-railway  service  in  a  number  of  cities  of 
the  United  States. 

The  "  cars  possible  to  be  supported"  column  shows  the  num- 
ber of  cars  that  could  make  a  living,  assuming  from  the  above 
discussion  that  400  passengers  must  be  carried  per  car  per 
day. 

The  last  column  shows  the  actual  number  of  cars  reported 
from  these  cities,  including  every  car,  running  or  not. 

The  increase  of  what  may  be  called  the  riding  co-efficient 
with  increase  of  total  population  appears  plainly  from  the 
table.  This  relation  is  displayed  more  clearly  by  the  above 
curve,  Fig.  126. 


324 


THE    ELECTRIC    RAILWAY 


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COMMERCIAL    CONSIDERATIONS. 


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326  THE    ELECTRIC    RAILWAY. 

In  endeavoring  to  treat  of  any  particular  case,  the  wide 
variations  from  which  the  above  averages  were  made  should 
be  borne  in  mind. 

It  has  become  a  common  practice  to  express  the  cost  of 
operating  as  a  certain  percentage  of  gross  earnings.  Such  a 
relation  is  a  useful  one  to  be  denned.  Yet  it  is  to  be  remem- 
bered that  unless  the  service  in  a  given  city  has  been  well 
studied  and  carefully  managed,  the  figures  shown  for  the 
actual  business  may  be  but  a  poor  guide  as  to  what  is  possi- 
ble. If  approximation  be  desired  and  this  method  be  used, 
operating  expense  may  be  taken  at  60  to  70  percent,  of  gross 
earnings. 

Experience  thus  far  shows  that  the  substitution  of  electric- 
ity for  horses  is  followed  by  an  increase  in  gross  receipts 
ranging  from  25  per  cent,  to  300  per  cent,  over  the  original 
receipts.  Even  when  the  service  with  horses  has  been  good 
considerable  increase  (rarely  less  than  30  per  cent.)  is 
marked.  No  better  evidence  could  be  had  of  the  desirability 
of  the  electric  railway.  The  expense  per  car-mile  will  gen- 
erally prove  to  be  less  than  by  horses.  We  say  generally, 
because  in  a  city  where  horses  and  forage  are  exceedingly 
cheap,  while  coal  and  mechanical  skill  are  unusually  high,  it 
might  be  impossible  to  secure  the  economy  usually  counted 
upon.  As  an  illustration  of  the  difference,  exemplified  on  a 
large  scale,  we  subjoin  a  statement  made  by  the  West  End 
Railway  Company  of  Boston,  showing  the  greater  economy 
per  car-mile  of -electric  traction.  It  is  to  be  noted  in  this 
case  that  the  figures  for  horses  represent  the  result  of  years 
of  effort  toward  the  best  attainable  practice,  while  for  electric 
traction  the  figures  cover  contract  prices  for  repairs  made 
very  early  in  the  history  of  the  business  and  consequently 
at  a  higher  price  than  would  now  be  made.  Moreover, 
the  practice  generally  being  new,  it  remains  for  time  to 
develop  those  small  economies  which  show  a  system  at  its 
best. 

For  both  horses  and  electricity  these  figures  of  cost  are 
high  as  compared  with  the  rates  attainable  elsewhere.  Coal, 
forage  and  labor  are,  in  Boston,  well  above  the  average  for 
the  entire  country.  Other  statements  are  also  given  in  a 


COMMERCIAL   CONSIDERATIONS. 


327 


OPERATIONS    OF   THE    WEST    END    STREET    RAILWAY 
CO.,  BOSTON,  MASS. 


1891. 

ELECTRIC 

Gross  receipts  

$134.321-00 

$144,638.00 

8145,31900 

$i44,553-oo 

$136,246.00 

General  expenses  

8,193.00 

7.796-00 

7,465  oo 

6,956.00 

Maintenance  expenses  

8,891.00 

8,078.00 

1  1  ,999.00 

12,498.00 

Transportation  expenses  

37,653.00 

36,55200 

31,556.00 

3-,895.°o 

31,123.00 

Motive  power  
Total  operating  expenses  

30,194.00 
85.835.00 

30,924.00 
84,163.00 

26,360.00 
73,459.00 

26.399.00 
77,249.00 

25,630.00 
75,278.00 

Net  earnings 

48,487.00 

71,860.00 

60,068.00 

Miles  run  

394,459 

376^321 

360,567 

377',i9i  °° 

363,836' 

Ratio  of  mileage  

26.68 

25-58 

25.15 

25.19 

24.92 

Per  cent,  operating  expenses  

63-36 

58.18 

50.55 

53-44 

57-'3 

EXPENSES  PER  MILE  RUN. 

CTS. 

CTS. 

CTS. 

CTS. 

CTS. 

Motive  power  per  mile  

07.65 

08.22 

07-31 

07.00 

07.04 

Car  repairs  per  mile  

01.39 

01.33 

01.18 

01.17 

01.57 

Damages  per  mile  

00.75 

00.89 

00.23 

Conductors  and  drivers  per  mile  

07-33 

07-36 

07.25 

06.92 

06.85 

Other  expenses  per  mile  
Total  expenses  per  mile  
Earnings  per  mile  run  

04.63 
21.75 

34-05 

04.56 
22.36 
38.43 

04.47 
20.37 
40.30 

05.27 
20.48 
38.32 

05.00 
20.69 

37-45 

Net  earned  per  mile  

12.30 

19.93 

17.84 

16.76 

1801 

HORSE. 

Gross  receipts  

8344,396-00 

8374.6o6.00 

8404,225.00 

$409,878.00 

$392,474.00 

General  expenses  

22,514.00 

22,682.00 

22,218.00 

20,657.00 

18,160.00 

Maintenance  expenses  
Transportation  expenses  

22,692.00 
114,001.00 

17,748.00 

18.560.00 
106,836.00 

27.228.00 

18,669.00 
105,953.00 

Motive  power  
Total  operating  expenses  

117,740.00 
276,947.00 

118,972.00 
269,556.00 

116,211.00 
263,825.00 

72,'888.oo 

"3,35i.oo 
256,133.00 

Net  earnings  
Miles  run.   . 
Ratio  of  mileage  

67,449.00 
1,083,887 
73-32 

105,049.00 
1,094,683 
74-42 

140,399.00 
1,073,218 
74-85 

36,990.00 
',  20,377 

136,341-00 
1,096,376 
75.08 

Per  cent,  operating  expenses  

80.62 

7"-95 

65-27 

[66.58 

64.52 

EXPENSES  PER  MILE  RUN. 

CTS. 

CTS. 

CTS. 

CIS. 

CTS. 

Motive  power  per  mile  

10.86 

10.86 

10.83 

w.38 

10.33 

Car  repairs  per  mile  

00.93 

00.60 

00.61 

00.03 

]  damages  per  mile  

00.78 

00.37 

00.15 

oo!o6 

Conductors  and  drivers  per  mile  

08.28 

08.24 

08.23 

otio 

OthT  expenses  per  mile  
Total  expenses  per  mile  
Earnings  per  mile  run  

04.70 
25-55 
31.77 

04-55 
24.62 
34-22 

04.74 

24.58 
37.66 

05-07 

33 

04.81 
23-37 
35.80 

Net  earned  per  mile  

06.22 

09.60 

12.23 

12.43 

Allowances  should  be  made  for  the  omission  of  cents  in  the  above  statement. 


328  THE    ELECTRIC    RAILWAY. 

foot-note,*  showing  results  obtained  elsewhere  on  a  somewhat 
smaller  scale. 

Those  companies  having  severe  snows  to  contend  with  must 
expend  a  considerable,  but  widely  variable,  amount  of  money 
in  order  to  clear  their  tracks.  In  some  of  our  most  northern 
cities  a  period  of  inaction  is  forced  by  the  magnitude  of  ex- 
pense that  would  be  incurred  in  clearing  tracks,  and  also 
because  such  effort  on  the  part  of  the  railway  company  would 
render  the  streets  unfit  for  the  service  of  "  runners" — wheeled 
vehicles  being  out  of  the  question  for  any  transportation. 

The  electric  snow-sweepers  now  being  put  on  the  market 
will  undoubtedly  diminish  the  interruption  to  traffic.  But 
they  will  demand  a  good  supply  of  power.  Even  with  their 
assistance  the  severe  winter  months  must  remain  but  slightly 
profitable.  The  average  road  lying  north  of  40°  north  latitude 


*  In  February  1891  President  D.  F.  Henry,  of  the  Federal  Street  and  Pleasant  Valley 
Passenger  Railway  Company  of  Pittsburg,  Pa.,  made  a  report  of  the  operation  of  the 
company  for  the  preceding  six  months,  in  which  was  embodied  some  interesting  infor- 
mation m  this  line.  We  quote  from  it  as  follows  . 

Passengers  carried,  six  months,  3,370,531  ;  receipts.  $168,526.55;  mileage,  31  cars,  averag- 
ing each  108  miles  per  day  ,  total  daily  average,  3,348  miles.  Cost  per  mile  : 

Conductors  and  motor-men per  mile,  6.80  cents. 

Motor  and  electric  repairs "  1.68 

Mechanical  repairs 1.14       " 

Motive  power  '•          1.54       " 

Overhead  system '•          0.45       " 

Maintenance  of  way "  1.08       " 

General  expense '•          0.88       " 

Stables •'          0.46      " 

Officers  and  salaries "          0.84       " 

Interests "          2.71       '% 

Tolls ••          0.25       " 

General  labor "          2.43       " 

Total 20.26  cents. 

as  total  cost  per  mile  of    operating    expense,   fixed  charges,   salaries  and  interest,    as 
against  receipts  per  car-mile  of  27.55  cents  ;  showing  net  earnings  per  mile  of  7.29  cents. 

Separating  the  above  into  strictly  operating  expense  and  fixed  charges,  we  have  oper- 
ating expense.  12.74  cents  per  mile  ;  and  in  comparing  the  same  with  the  cost  of  operating- 
the  horse  line,  which  was,  10  cents  per  car-mile,  we  must  remember  that  we  then  paid  but 
one  man  on  a  car.  where  we  now  pay  four,  or  3  cents  per  mile,  against  6.80  cents  now. 
This  increased  cost  per  mile  for  conductors  and  motor-men  is  a  necessary  adjunct  of  rapid 
transit,  and  is  not  peculiar  to  the  system.  Allowing  for  this,  we  have  a  difference  of  1.04 
cents  per  car-mile  in  favor  of  electricity  as  against  animal  power. 

1  call  attention  to  the  fact  that  'we  have  one  of  the  most  difficult  roads  in  existence 
to  operate,  with  streets  having  over  one  hundred  curves,  many  of  which  have  a  short 
radius,  and  with  heavy  grades,  leaving  but  little  straight  and  level  roadway.  We  have 
also  six  steam  and  six  cable  railway  crossings. 

President  John  N,  Beckley  of  the  Rochester  Railway  Company,  at  a  recent  meeting 
of  the  Street  Railway  Association  of  the  State  of  New  York,  gave  the  following  as  the 
result  of  the  experience  of  his  company 

n  the  month  of  May  last  the  Rochester  Railway  Company  operated  44  18  foot  vestibule 
electric  cars.  The  gross  receipts  from  passengers  riding  on  these  cars  during  the  month 


COMMERCIAL    CONSIDERATIONS.  329 

in  the  United  States  will  not  be  wide  of  the  mark  in  calculat- 
ing that  its  profits  must  be  made  in  nine  months  of  the 
twelve — the  other  three  just  paying  their  own  expenses. 

As  an  assistance  in  the  commercial  management  of  an 
electric  railway  we  give  in  Appendix  D  a  set  of  accounting 
rules.  These  were  very  carefully  prepared  by  Mr.  H.  I. 
Bettis,  of  Boston,  while  serving  as  auditor  of  the  accounts  of 
the  Thomson-Houston  Electric  Company,  in  their  contract 
work  of  maintaining  electric  equipment  and  lines  of  the  West 
End  Railway  Company — the  work  being  under  the  direction 
of  Mr.  W.  E.  Baker.  Mr.  Baker  has  kindly  added  to  these 
rules  a  few  words  on  the  economical  organization  and  ad- 
ministration of  the  working  force  of  an  electric  railway. 

A  comprehensive  statement  of  monthly  operations  may  be 
made  on  a  form  similar  to  form  "C."  It  will  be  seen  on  this 


were  $37,053,  or  23.15  cents  per  car-mile  for  a  mileage  of  159,567  miles.  The  total  expense  of 
operation  of  these  cars  for  that  month  was  $18,332,  thus  leaving  a  net  profit  of  $18,721. 
The  total  cost  of  operation  per  car-mile  was  11.4  cents,  and  the  profit  per  car-mile  was 
therefore  12.11  cents  It  may  be  observed  in  passing  that  the  operating  expense  was  a 
trifle  under  50  per  cent,  of  the  gross  receipts  The  cost  of  operating  was  divided  as 
follows  : 

Motive  power 2.8   cents. 

Car  repairs 0.7 

Conductors  and  motor-men 4.9        " 

Other  expenses 3.0 

During  the  same  period  the  company  operated  62  horse  cars,  all  of  them  without  con- 
ductors. Most  of  the  horse  cars  were  one-horse  or  bobtail  cars.  The  total  cost  of  operat- 
ing the  horse  cars,  without  conductors,  during  this  period  was  about  10  cents  per  car- 
mile,  but  the  total  receipts  per  car-mile  were  but  little  above  12  cents. 

In  the  month  of  June  the  Rochester  Railway  Company  operated  54  electric  cars  and  60 
horse  cars.  The  electric  cars  earned  each  per  day  $23.60,  or  22.77  cents  per  car-mile,  and 
the  total  expense  of  operating  them  per  day  was  $10.50,  or  11.07  cents  per  car-mile.  The 
cost  of  operation  per  car-mile  was  divided  as  follows  : 

Motive  power 2.40  cents. 

Car  repairs i.oo       " 

Conductors  and  motor-men 5.66       " 

Other  expenses 2.01       '' 

Making  a  total  per  car-mile  of 1 1.07  cents 

The  cost  of  operating  the  horse  cars  during  the  same  month  per  car-mile  was  11.06 
cents,  and  they  earned  14.37  cents  per  car-mile.  My  experience  in  the  operation  of  street 
railroads  has  convinced  me  that  the  most  economical  system  of  operation  is  the  electric 
system.  I  have  not,  in  the  statements  which  I  have  now  made,  taken  into  consideration 
the  greater  fixed  charge  in  the  operation  of  an  electric  railroad  as  compared  with  a  horse 
rnilroad,  due  to  the  much  greater  cost  of  the  former;  but  in  arriving  at  the  conclusion 
which  I  have  above  expressed,  due  consideration  has  been  given  to  this  element  of 
increased  cost.  We  know  that  when  a  horse  railroad  is  changed  over  and  operated  by 
electricity  the  receipts  are  very  largely  increased.  It  is  safe  in  any  case  to  say  that  the 
increase  in  gross  receipts  will  be  at  least  15  per  ce.it.,  and  the  average  increase  is 
probably  as  high  as  30  per  cent.  Some  of  the  increase  is  undoubtedly  due  to  the  greater 
mileage  which  the  cars  make,  and  still  more  is  due  to  the  cleaner,  more  rapid  and  more 
comfortable  transportation  of  the  people. 


330 


THE    ELECTRIC    RAILWAY. 


form  that  the  final  result  of  a  month's  operation  is  expressed 
in  four  different  manners — namely,  per  cent,  of  expenses  to 
earnings,  net  earnings,  expense  per  car-mile,  and  expense 
per  passenger.  All  these  have  a  certain  value  for  comparison. 
Neither,  alone,  tells  the  whole  story. 

The  next  matter  is  how  to  arrive  at  and  keep  those  ex- 
penses sufficiently  accurately  and  without  too  much  clerical 
labor;  and  this  brings  us  primarily  to  the  stock  or  supply 
account.  All  material  while  in  the  stock  room,  and  until 
used,  evidently  bears  the  same  relation  to  the  company  as 
cash  in  the  till  or  bank,  except  for  availability,  and  should 
be  so  treated.  Material  should  not  be  charged  to  the  expenses 
of  the  road  until  used,  and  should  be  charged  when  used, 
regardless  of  the  bill  for  this  material  being  received  or  paid. 

A  careful  record  should  be  kept  of  all  material  'received 
and  all  material  used  on  blanks  somewhat  similar  to  forms 
"  E"  and  "  D,"  bound  in  book  form.  It  is  sometimes  consid- 
ered better  to  have  the  form  "  D"  on  loose  sheets  instead  of 
bound,  and  there  are  apparent  variations  to  be  made  in  the 
blank  to  suit  individual  cases. 

The  "  Material  Received"  book,  or  form  "  E,"  will  be  found 
to  pay  for  itself  in  checking  bills  and  preventing  duplication. 
The  material  used  is  arrived  at  by  charging  out  of  the  stock 
room  on  "Foreman's  Requisition,"  in  small  quantities,  as 
used,  or  obliging  a  foreman  lo  make  on  a  proper  form  a  daily 
or  weekly  or  monthly  report  of  the  material  he  uses.  A 
simple  form  is  that  of  form  "F."  One  man  should  receive 
all  the  material  for  the  road ;  he  may,  of  course,  be  a  store- 
keeper for  this  purpose  if  the  road  is  sufficiently  extensive ;  or, 
if  not,  this  duty  may  be  added  to  the  other  duties  of  the  clerk. 

An  invoice  book  with  copies  of  all  bills  should  be  kept, 
and  a  monthly  summary  of  both  books  should  be  made — giv- 
ing from  the  invoice  book  all  the  charges  to  stock,  and  from 
the  material  used  all  the  credit  to  stock,  and  all  the  charges 
of  material  to  expense  properly  classified.  If  in  addition  a 
stock  ledger  is  kept,  it  will  be  found  that  all  errors  and  mis- 
takes in  foreman's  and  clerk's  pricing,  etc.,  will  correct 
themselves ;  and  it  will  be  easy  at  any  time  to  check  up  the 
ledger  with-the  material  actually  on  hand  in  the  stock  room. 


COMMERCIAL   CONSIDERATIONS.  33! 

In  regard  to  the  labor,  there  are  many  forms  of  time  books 
used;  the  one  here  presented  as  form  "  P"  is  convenient, 
and  the  foremen  soon  learn  to  classify  their  time  with  little 
trouble  and  few  mistakes.  On  the  pay  roll  should  be  classi- 
fied these  expenses,  and  the  total  of  all  expenses  is  thus 
easily  found. 

The  mileage  sheets  from  "  A"  will  be  found  very  complete, 
and  will  give  a  record  of  the  mileage  of  each  car  per  month. 
The  original  records  can  be  taken  from  the  conductor's 
report  most  easily  on  a  blank  book,  and  transferred  to  these 
reports  monthly.  The  conductor's  reports  should  cover  a 
report  of  the  number  of  passengers  carried  on  each  trip,  the 
number  of  trips  made,  and  the  route.  There  are  many 
excellent  forms  for  these. 

To  summarize,  if  the  superintendent,  as  is  frequently  the 
case,  has  an  office  distinct  from  the  office  of  the  company,  he 
would  be  required  to  have  the  following  books :  stock  ledger, 
time  book,  pay  rolls,  material  used  and  material  received 
books.  Copy  books  as  follows  will  be  found  convenient:  A 
letter  book,  a  copy  book  for  pay  rolls,  a  requisition  book  (un- 
less he  buys  his  own  supplies  wholly,  when  this  becomes  an 
order  book),  a  daily  report  of  earnings  book  or  deposit  book, 
a  motor  report  book  for  copying  reports  made  on  blank  form 
"S,"and  a  statement  and  bill  copying  book  for  bills  made 
against  other  parties.  Monthly  reports  should  be  made  about 
as  follows:  mileage  report,  material  used,  balance  of  stock 
ledger,  receipts  report,  invoice  summary.  The  daily  re- 
ports would  be  of  daily  earnings  and  of  condition  of  motor 
cars. 

On  a  road  of  any  considerable  size,  say  of  20  cars  and 
upward,  the  superintendent  will  need  the  assistance  of  six 
good  men — namely,  a  chief  conductor,  engineer  at  power 
house,  line  foreman,  foreman  of  car  repairs,  foreman  of  track, 
and  clerk ;  and,  in  fact,  this  organization  will  need  only  to 
be  extended  to  operate  a  road  of  the  largest  size,  when  the 
foreman  of  car  repairs  becomes  the  master  mechanic,  the 
clerk  the  auditor,  etc. 

As  to  the  force  employed  with  an  equipment  of  two  15 
horse-power  motors  per  car,  we  can  allow  about  as  follows: 


332  THE    ELECTRIC    RAILWAY. 

One  day  mechanic  to  12  cars. 

One  inspector  to  50  cars. 

One  cleaner  to  1 5  cars. 

The  motors  ought  to  be  cleaned  thoroughly  every  third 
day.  When  less  than  25  cars  are  run  from  one  car  house, 
the  repair  foreman  may  take  the  place  of  one  mechanic,  and 
in  case  less  than  12  cars  are  run  from  one  car  house  one 
mechanic  may  do  the  cleaning  and  repair  work.  The  fore- 
man will  be  in  addition  to  the  figures  given,  and  these  men 
will  take  care  of  the  motors  only;  if  additional  work  is  re- 
quired to  any  extent  in  repairs  of  the  car  bodies,  etc.,  more 
men  will  be  needed. 

A  proper  manner  to  handle  the  bills  for  supplies  and  ex- 
pense is  as  follows :  provide  a  stamp  with  which  every  bill  can 
be  stamped  on  receipt,  and  which  provides  a  place  for  the 
storekeeper  to  certify  that  the  goods  have  been  received,  and 
have  the  bill  checked  and  a  place  for  a  clerk  to  certify  that 
any  extensions  and  additions  on  the  bill  are  correct;  also  a 
place  for  the  same  person  ordering  the  goods  to  certify  to  the 
same ;  lastly,  a  place  for  the  approval  of  the  superintendent. 
It  is  important  that  all  the  names  be  written  on  the  bill  certi- 
fying to  these  facts,  as  then  the  whole  history  of  the  bill  can 
at  any  time  be  ascertained. 


CHAPTER    XII. 

HISTORICAL   NOTES. 

THE  history  of  the  electric  railway  presents  some  very 
curious  features.  Important  though  this  particular  applica- 
tion of  electricity  is  to-day,  it  is  almost  impossible  to  trace 
out  the  various  steps  in  its  development  with  anything  like 
certainty  of  giving  credit  to  whom  credit  is  due.  For  not  only 
has  the  electric  railway  been  a  gradual  evolution  of  ideas  in 
the  hands  of  many  inventors  working  almost  simultaneously, 
but  it  is  almost  unique  in  that  it  was  worked  out — so  far  as, 
invention  is  concerned — during  two  distinct  periods ;  first, 
at  the  time  when  the  only  source  of  electricity  was  the  bat- 
tery, and  then  over  again  after  a  commercial  source  of  elec- 
tric current  had  been  found  in  the  dynamo. 

So  long  as  the  efforts  of  inventors  were  confined  to  the  use 
of  batteries,  almost  nothing  could  be  done  in  the  way  of 
practical  electric  railway  work;  for  its  cost  was  evidently  so 
prohibitive  as  to  deter  inventors  from  spending  time  and 
money  on  the  solution  of  the  various  problems  involved.  Not 
until  the  modern  dynamo  had  been  invented  and  the  great 
principle  of  its  reversibility  discovered  was  it  possible  to 
bring  electric  motive  power  to  anything  like  a  practical  state. 

This  fact  of  there  being  two  distinct  periods  of  evolution 
in  the  history  of  the  electric  railway  has  had,  perhaps,  a 
happy  effect  on  its  modern  development,  in  that  the  funda- 
mental principles  and  methods  had  already  become  the 
common  property  of  inventors,  and  hence  the  growth  of  the 
art  has  not  as  yet  been  checked  by  any  basic  patents  of  so 
formidable  a  description  as  to  deter  improvement  on  the 
part  of  others  than  some  single  individual  or  company. 

The  inception  of  the  electric  railroad  and  the  first  period 
of  its  history  had  its  scene  of  action  in  the  United  States ; 
the  working  out  of  the  broad  principles  on  which  modern 

333 


334  THE    ELECTRIC    RAILWAY. 

electric  traction  is  based,  and  the  first  great  steps  toward 
the  reduction  of  these  principles  to  practice,  took  place 
abroad ;  and  then  again  the  scene  changed  back  to  America 
so  completely  that  one  may  say,  without  risk  of  doing  any 
injustice,  that  electric  traction  as  a  whole  is  of  American 
development. 

The  electric  motor,  from  which  has  sprung  so  many 
important  practical  applications,  may  probably  be  said  to 
have  had  its  origin  in  the  Barlow  wheel  in  1826;  and,  oddly 
enough,  this  first  effort  was  the  forerunner  of  a  rather  ad- 
vanced type  of  machine,  being  the  motor  counterpart  of 
Faraday's  disk  machine  and  the  unipolar  dynamos  of  later 
years.  Inventors  were  to  pass  through  a  long  period  of  per- 
plexity and  roundabout  expedients  before  they  came  back 
again  to  the  principle  of  a  reversed  dynamo. 

In  1830  the  Abbe  Salvatore  Dal  Negro,  an  Italian,  pro- 
fessor of  natural  philosophy  in  the  University  of  Padua,  de- 
vised a  reciprocating  form  of  motor  in  which  a  permanent 
magnet  oscillated  between  the  poles  of  an  electro-magnet 
commutated  at  each  movement.  A  year  or  two  later  many 
inventors  worked  in  the  same  line,  but  the  first  step  toward 
the  electric  railroad  was  taken  b)'  Thomas  Davenport,  a 
blacksmith  living  in  Brandon,  Vt.,  who,  quite  independently 
of  previous  researches,  devised  a  rudimentary  electric  motor 
working  on  the  general  principle  of  revolving  an  electro- 
magnet by  its  attraction  for  fixed  armatures  or  magnets,  the 
current  being  commutated  at  the  proper  time  to  let  the  poles 
pass  the  first  set  of  armatures  and  take  up  the  work  at  the 
next.  This  he  applied  to  an  automobile  electric  car  supplied 
by  batteries  carried  upon  it,  and  as  early  as  1835  he  con- 
structed a  little  circular  electric  road. 

This  was  exhibited  during  the  autumn  of  1835  in  Spring- 
field, Mass.,  and  also  for  two  weeks  in  December  of  the  same 
year  in  Boston.  The  road  consisted  of  an  automobile  car  car- 
rying its  own  batteries.  Of  course  nothing  came  of  this  rudi- 
mentary experiment,  and  the  first  extension  of  the  same  idea 
was  at  the  hands  of  Robert  Davidson,  of  Aberdeen,  Scotland, 
who  resides  there  to-day — perhaps  the  oldest  living  electri- 
cian. He  began  his  experiments  about  1838,  at  the  period 


HISTORICAL    NOTES.  335 

when  wide  attention  was  called  to  the  possibilities  of  the 
electric  motor  by  its  use  in  the  hands  of  Jacobi  for  propelling1 
a  small  boat  on  the  river  Neva.  The  power  in  this  case  was 
furnished  by  primary  batteries,  and  the  speed  reached  by  the 
boat — 28  feet  long  and  7  feet  beam — about  3  miles  per  hour. 

Davidson  was  filled  with  the  idea  that  the  electric  motor 
would  find  a  place  in  the  ordinary  locomotive  work  of  rail- 
ways. He  built  with  this  in  view  a  powerful  motor,  and 
fitted  it  on  a  truck  of  the  ordinary  railway  gauge.  The  motor 
carried  batteries  for  supplying  the  power;  it  was  16  feet 
long,  5  feet  wide,  and  its  total  weight — including  the  bat- 
teries— was  about  5  tons;  40  battery  cells,  were  employed,  of 
a  type  claimed  by  Davidson  as  his  own,  although  this  was 
disputed  by  Mr.  Sturgeon  and  J.  Martin  Roberts.  The  ele- 
ments consisted  of  plates,  12  by  15  inches  in  size,  of  iron  and 
of  amalgamated  zinc  immersed  in  dilute  sulphuric  acid. 
The  current  obtained  from  these  was  delivered  to  an  electric 
motor  consisting  of  a  pair  of  drums,  each  bearing  two  sets  of 
iron  bars  parallel  to  the  axles.  Eight  electro-magnets  were 
placed  on  the  bottom  of  the  car  in  two  opposite  rows,  and 
put  the  drums  in  rotation  by  attracting  the  armatures  fas- 
tened upon  them,  while  a  commutator  revolving  with  the 
armatures  made  the  necessary  changes  of  current  in  the 
magnets.  Davidson's  experiments  are  principally  interest- 
ing on  account  of  the  large  scale  on  which  they  were  carried 
out.  The  locomotive  just  mentioned  made  several  successful 
trips  on  some  of  the  Scottish  railways,  and,  finally,  while  the 
machine  was  being  taken  home  to  Aberdeen,  it  was  found 
one  morning  in  the  engine-house  at  Perth  shattered  beyond 
repair  by  some  mischief -making  intruder.  The  railway  en- 
gineers of  the  time  felt  very  strongly  that  this  innovation 
might  be  destined  to  supersede  their  own  machines,  and 
evidence  pointed  to  the  destruction  of  this  first  electric  loco- 
motive as  having  been  at  their  hands. 

After  the  Davidson  experiments  nothing  on  so  large  a 
scale  was  attempted  for  more  than  a  decade,  when  Prof.  C. 
G.  Page,  of  the  Smithsonian  Institution,  well  known  as 
a  versatile  genius  in  many  fields  of  research,  took  up 
the  subject  of  the  application  of  the  electric  motor  to 


236  THE    ELECTRIC    RAILWAY. 

railroading  and  performed  some  exceedingly  interesting 
experiments. 

Page,  like  Davidson,  was  thoroughly  persuaded  that  the  elec- 
tric motor  might  be  successfully  used  in  regular  railway  work, 
and  a  machine  of  10  horse-power  was  built  by  him  in  1850. 
The  general  design  followed  was  similar  to  a  steam  engine, 
two  solenoids  replacing  the  cylinder,  and  drawing  backward 
and  forward  a  soft  iron  piston  rod  which  actuated  a  fly-wheel 
by  means  of  an  ordinary  connecting  rod  and  crank,  while  the 
motion  of  the  piston  shifted  the  connections  from  one  solenoid 
to  the  other  at  the  end  of  the  stroke. 

From  this  design  he  passed  to  that  of  two  double  solenoids 
acting  on  U-shaped  magnet  cores  in  a  precisely  similar  way, 
and  he  eventually  wound  his  solenoids  in  sections  so  that 
by  a  sliding  commutator  the  current  could  be  so  applied  as  to 
produce  both  a  long  and  a  strong  pull. 

His  first  experiment  with  the  electric  locomotive  made  on 
this  model  was  tried  April  29,  1851,  along  the  Washington 
and  Baltimore  Railroad  to  Bladensburg.  This  later  machine 
was  of  1 6  horse-power,  and  derived  its  supply  of  electrical 
energy  from  100  large  flat  Grove  cells  stored  on  the  locomo- 
tive, each  having  platinum  plates  1 1  inches  square. 

The  speed  attained  in  this  experiment  was  quite  high, 
being  at  some  points  in  the  run  at  the  rate  of  19  miles  an 
hour.  Trouble  was  encountered,  however,  from  breakage  of 
the  light  earthenware  porous  cups,  and  after  several  subse- 
quent'experiments  Prof.  Page  dropped  the  subject,  having 
proved  that  considerable  power  and  speed  could  be  obtained 
at,  however,  a  prohibitive  cost. 

Two  other  experiments  on  electric  railroading,  at  about 
the  same  time,  are  worth  mentioning,  although  on  a  very 
small  scale.  One  was  by  Prof.  Moses  G.  Farmer,  who  built 
a  model  locomotive,  running  on  a  track  of  1 8-inch  gauge  and 
carrying  a  small  car,  which  could  accommodate  two  passen- 
gers. The  power  supplied  was  but  small,  furnished  by  48 
pint  cells  of  Grove  battery.  In  1851  he  built  another  little 
model  road,  which  is  important  as  showing  a  decided  devel- 
opment in  the  art.  It  was  constructed  by  Mr.  Thomas  Hall, 
of  Boston,  Mass.,  and  was  exhibited  at  the  Charitable  Me- 


HISTORICAL   NOTES.  337 

chanics'  Fair.  The  track  on  which  it  ran  was  40  feet  long, 
and  the  gauge  was  but  5  inches.  The  motor  was  such  an  one 
as  had  been  frequently  used  by  Page  and  others,  consisting 
merely  of  a  permanent  magnet,  with  an  electro-magnet,  pro- 
vided with  a  suitable  commutator,  rotating  between  its  poles. 
This  armature  shaft  was  provided  with  a  worm,  which  en- 
gaged the  teeth  of  an  intermediate  gear  wheel  that  drove 
the  axle. 

The  track  was  so  arranged  that  when  the  car  reached  either 
end  of  it  a  pole  changer  would  automatically  be  thrown  over 
and  reverse  the  direction  of  motion.  The  specially  interest- 
ing feature  of  this  road,  however,  is  the  fact  that  the  current 
was  supplied  to  the  motor  through  the  rails,  and  not  from 
batteries  carried  on  the  car ;  further,  the  motor  armature  was 
geared  to  the  driving  axle  with  a  considerable  speed  reduc- 
tion, which  embodied  the  principle  of  economical  working 
that  has  since  been  generally  followed. 

This  model  of  Mr.  Hall's  very  plainly  shows  the  combina- 
tion of  a  moving  motor  car  supplied  from  a  stationary  source 
of  energy,  and,  with  some  similar  anticipations,  has  gone  far 
to  prevent  any  fundamental  patents  from  being  granted  dur- 
ing the  second  stage  of  the  development  of  the  electric  rail- 
road. In  fact,  the  same  idea  had  been  disclosed  four  years 
previously  by  Mr.  Lilley  and  Dr.  Colton,  of  Pittsburg. 
Their  device  was  simply  a  little  model  electric  locomotive 
running  around  a  circular  track.  The  rails  were  insulated, 
and  one  was  connected  with  each  pole  of  the  battery. 

In  1840,  however,  a  provisional  patent  had  been  granted 
in  England  to  Henry  Pinkus,  in  which  not  only  was  the 
general  idea  of  supplying  current  to  a  moving  train  from  a 
fixed  source  plainly  shown,  but  it  was  even  suggested  that 
an  electric  motor  might  be  used  to  drive  the  train  itself. 
The  patent  had  primary  reference  to  ordinary  railroad  work, 
and  its  provisions  are  not  very  clear ;  but  the  idea  was  very 
distinctly  put,  and  Pinkus  even  suggested  the  possible  use 
of  mechanical  generators  to  replace  the  batteries  shown  in 
his  plans. 

It  may  also  be  mentioned  that  an  English  patent  to  Swear, 
in  1855,  on  telegraphy  from  moving:  trains,  involved  in  a  very 


338  THE   ELECTRIC    RAILWAY. 

obvious  way  the  idea  of  taking  current  from  an  uninsulated 
conductor  running  along  the  line,  thus  forestalling  the  mod- 
ern trolley  system. 

The  same  principles  are  shown  and  described  in  French 
and  Austrian  patents  granted  to  Major  Alexander  Bessolo  in 
1855.  The  French  patent  shows  what  is  now  known  as  the 
third-rail  system,  with  the  return  through  the  ordinary  rails. 
It  was  proposed  originally  for  train  telegraphy,  as  in  the 
case  of  Pinkus  and  others.  Bessolo  also  stated  that  he  pro- 
posed to  use  an  overhead  wire  for  one  side  of  the  circuit  and 
the  rail  for  the  other,  the  current  being  taken  from  a  sta- 
tionary generator.  In  a  supplemental  specification  to  the 
Austrian  patent  the  inventor  explained  that  he  proposed  to 
use  this  system  of  distribution  for  driving  vehicles  on  ordi- 
nary roads  and  on  railways,  and  stated,  as  in  the  French 
patent,  that  the  current  may  be  conveyed  to  the  locomotive 
machine  by  means  of  a  circuit  formed  by  a  conductor  insu- 
lated from  the  ground  and  suspended  in  a  manner  analogous 
to  telegraph  wires  and  by  the  rails  of  the  track.  Bessolo 
further  suggests  that  such  a  system  of  locomotion  would  have 
great  advantages  on  account  of  the  ability  of  the  current  easily 
to  reach  independent  locomotives  or  vehicles  composing 
small  trains,  and  that,  besides,  the  generators  were  to  be  so 
located  that  they  could  be  controlled  from  the  stations. 

All  these  early  efforts  at  electric  traction,  however,  resulted 
in  nothing  practical,  for  the  simple  reason  that  power  had  to 
be  derived  from  batteries  and  was  consequently  too  expensive 
for  commercial  use.  It  was  not  until  the  dynamo  had  ap- 
peared and  the  principle  of  its  reversibility  had  been  estab- 
lished that  anything  could  be  hoped  for  along  this  partictilar 
line  of  progress. 

In  1864  Pacinotti  made  his  now  famous  electro-magnetic 
machine,  and,  crude  though  it  was,  and  unappreciated  at  the 
immediate  time,  it  was  the  forerunner  both  of  the  modern 
dynamo  and  motor ;  for  Pacinotti  understood  perfectly  well 
that  his  machine  was  reversible,  and  that  if  current  were 
supplied  to  it  power  could  be  obtained ;  while  if  power  were 
supplied  current  could  be  obtained. 

Three  years 'later  Wheatstone  and  Siemens,  independently 


HISTORICAL   NOTES.  339 

and  almost  simultaneously,  devised  self-exciting  dynamos — 
that  of  the  former  being  shunt  wound,  that  of  the  latter 
series  wound ;  and  at  about  the  same  time  Siemens  found 
that  his  machine  could  be  used  as  a  motor,  although  his 
discovery  produced  no  immediate  results. 

He  is  said,  however,  at  that  period  to  have  contemplated 
its  adaptation  to  electric  traction.  Six  years  later  the  use  of 
the  dynamo  as  a  motor  was  clearly  demonstrated  by  Messrs. 
Fontaine  and  Breguet  at  the  Vienna  Exposition.  Just  pre- 
vious to  this  time  Siemens  and  Gramme  had  brought  out 
commercial  machines,  and  the  latter  had  observed  in  his 
workshop  that  his  dynamo  could  be  used  as  a  motor. 

Fontaine  and  Breguet  had  intended  to  exhibit  the  principle 
by  running  one  of  the  dynamos  as  a  motor  from  a  primary  or 
secondary  battery,  but  failing  in  this  they  coupled  two  ma- 
chines together,  and  finding  that  the  experiment  was  thor- 
oughly successful,  used  the  motor  to  drive  a  pump  at  the 
formal  opening  of  the  Machinery  Hall,  June  3,  1873. 

The  experiment,  of  course,  created  a  great  sensation,  and 
during  the  next  four  years  it  became  familiar  in  lectures,  and 
was  on  a  few  occasions  used  for  the  transmission  of  a  small 
amount  of  power.  The  scene  of  action  now  shifted  to 
America,  and  the  experiments  of  Mr.  George  F.  Green,  of 
Kalamazoo,  Mich.,  began.  Green  was  a  poor  mechanic,  but 
possessed  of  more  than  ordinary  skill  and  ingenuity,  and  for 
years  had  been  interested  in  the  study  of  electricity.  About 
1875  his  ideas  took  shape,  and  he  constructed  a  little  model 
electric  railway  quite  similar  to  that  devised  by  Farmer,  but 
on  a  somewhat  larger  scale. 

Green  used  the  track  rails  to  transmit  the  current  from  the 
source  of  electricity — a  battery  in  his  experiments — to  the 
moving  car,  which  was  driven  by  a  small  electric  motor  of 
the  pole-changing  type.  He  also  proposed,  as  shown  by  his 
drawings  of  that  date,  to  use  an  overhead  wire  as  one  of  the 
sides  of  the  circuit,  but  the  experiment  was  not  carried  out. 

During  the  next  few  years  he  was  working  at  the  problem 
as  steadily  as  his  occupation  permitted,  and  in  1878  or  1879 
built  a  larger  model,  with  a  car  large  enough  to  seat  one  or 
two  people,  propelled  in  substantially  the  same  way. 


34o  THE    ELECTRIC    RAILWAY. 

He  fully  understood  the  advantages  of  employing  a  dynamo 
instead  of  batteries,  but  no  dynamo  was  available  for  the 
experiments.  Not  until  August,  1879,  did  he  apply  for  pat- 
ents; and  then,  through  lack  of  funds,  he  was  obliged  to  act 
as  his  own  patent  attorney,  with  the  customary  result  of 
encountering  great  difficulties  in  the  Patent  Office.  He  went 
into  interference  with  other  inventors,  and  his  claims,  after 
being  rejected  on  appeal  to  the  Commissioner  of  Patents, 
were  taken  to  the  Circuit  Court  of  the  District  of  Columbia, 
which  tribunal  alone  has  the  right  to  order  a  patent  issued 
under  such  circumstances. 

Here  he  was  successful,  but  it  was  not  until  the  latter  part 
of  1891  that  the  decision  was  finally  reached,  and  in  December 
a  patent  was  issued  covering  more  broadly  than  would  a  pri- 
ori be  supposed  possible  the  principles  of  the  electric  railway. 
His  experiments  formed  the  connecting  link  between  the 
older  and  the  newer  period  of  inventions  in  the  line  of  electric 
traction. 

It  was  not  until  1879,  however,  that  the  electrical  trans- 
mission of  energy  was  taken  up  on  a  serious  scale.  On 
Ascension  Day,  1879,  there  was  carried  out  at  the  little  vil- 
lage of  Sermaize,  near  Paris,  by  Chretien  and  Felix,  an  ex- 
periment on  plowing  by  electricity  which  marks  so  decided  an 
epoch  in  the  subject  as  to  be  worthy  of  more  than  a  hasty  de- 
scription, particularly  as  it  has  been  too  lightly  passed  over  in 
most  historical  notes  on  the  transmission  of  power. 

Plowing  by  steam  power  had  already  been  tried  in  England 
and  the  United  States,  and  it  occurred  to  the  engineers  who 
instituted  this  notable  experiment  that  the  electric  transmis- 
sion of  power  offered  great  opportunities  in  facilitating  the 
convenient  application  of  mechanical  power  to  such  tasks.  A 
rectangular  plot  of  ground  220  meters  wide  had  been  laid  out 
for  the  experiment,  and  the  method  employed  was  to  estab- 
lish at  each  end  of  a  furrow  a  massive  wagon  carrying  a 
motor,  dragging  a  double-ended  gang-plow  by  means  of  a 
cable  and  drum.  A  similar  device  had  been  previously  used 
in  steam  plowing  with  tolerable  success. 

In  this  case  there  was  mounted  on  each  wagon  a  "  type  A" 
Gramme  machine  of  the  sort  ordinarily  used  for  electric 


HISTORICAL   NOTES.  34! 

lighting;  these  two  were  united  by  a  conductor  250  meters 
long,  forming  part  of  a  complete  metallic  circuit  of  copper 
wire  3  millimeters  in  diameter  connecting  them  with  two 
precisely  similar  Gramme  machines  for  furnishing  power. 
These  two  generators  were  distant,  at  various  times  during 
the  experiment,  from  400  to  620  meters  from  the  motors. 

The  wagons  themselves  were  automobile,  as  an  axle  of 
each  could  be  driven  by  means  of  throwing  the  motor  into 
gear  with  a  large  gear  wheel  connected  to  a  wheel  upon  the 
axle  by  a  sprocket  chain.  Probably  about  3  horse-power  was 
developed  at  the  motors  in  this  experiment,  which  was  en- 
tirely successful.  The  speed  reached  by  the  plow  was  40  to 
50  meters  per  minute.  The  drums  on  which  was  wound 
the  cable  were  driven  by  the  motors  through  the  interven- 
tion of  friction  gearing. 

The  power  was  supplied  from  the  Sermaize  beet  sugar 
factory,  and  during  the  latter  part  of  the  previous  season 
(1878)  Chretien  and  Felix  had  arranged  at  the  river  front, 
about  100  yards  distant  from  the  factory,  an  electric  hoist 
operated  from  the  machines  in  the  factory  and  serving  to 
transfer  the  beet  root  from  the  boats  in  which  it  was  brought 
down  the  river  to  the  factory  wagons.  Up  to  the  time  of 
the  famous  plowing  experiment  some  4,000  tons  had  been 
thus  handled,  at  a  cost  of  40  per  cent,  less  than  unloading 
by  hand. 

The  experiments  just  mentioned  are  in  all  probability  the 
first  examples  of  the  transmission  of  power  on  a  considerable 
scale  either  to  fixed  or  movable  motors. 

During  the  summer  of  1879  the  first  electric  railway  was 
put  in  operation,  by  the  firm  of  Siemens  &  Halske,  at  the 
Industrial  Exposition  in  Berlin.  An  oval  track  about  300 
meters  in  circumference  was  laid  down,  and  upon  it  ran.  a 
little  electric  locomotive  dragging  a  single  platform  car.  A 
third  rail  placed  midway  between  the  others  served  as  the 
working  conductor,  and  the  current  was  taken  from  it  by 
means  of  a  sliding  contact  under  the  locomotive.  The  motor 
used  was  one  of  the  regular  Siemens  dynamos,  placed  with 
its  armature  spindle  parallel  to  the  track ;  and  the  power  was 
transmitted  to  the  axle  by  a  double-gear  reduction,  including, 


342  THE    ELECTRIC    RAILWAY. 

of  course,  a  pair  of  bevel  gears.  The  outer  rails  served  as  a 
return  for  the  current  through  the  wheels  of  the  locomotive. 
Eighteen  or  20  passengers  constituted  the  full  load  of  the 
little  train,  and  the  time  required  for  a  complete  circuit  was 
from  one  to  two  minutes,  corresponding  to  a  speed  of  perhaps 
8  miles  per  hour. 

This  road  is  notable  as  being  the  practical  starting-point 
of  modern  electric  traction.  It  is  beyond  all  question  the  first 
working  electric  railroad  on  a  practical  scale.  Up  to  that 
time  nothing  had  been  constructed  which  bore  even  the  sem- 
blance of  a  commercial  electric  railway,  and  such  few  plans 
as  had  existed  before,  both  in  Europe  and  America,  were 
mainly  on  paper. 

The  success  of  the  Berlin  experiments  stimulated  invention 
in  every  part  of  the  world,  and  the  natural  result  was  repeti- 
tion of  them  under  varied  conditions  and  in  different  places. 
During  the  exposition  at  Vienna  in  the  succeeding  year  Egger 
showed  a  model  electric  railway  in  which  the  third  rail  was 
dispensed  with  and  the  two  working  rails  alone  constituted 
the  metallic  circuit.  Very  early  in  the  same  year  Siemens 
had  been  negotiating  with  the  city  authorities  of  Berlin  for 
a  franchise  for  an  electric  road  on  a  considerable  scale. 
About  the  same  time  some  experiments  were  conducted  in 
Paris  with  a  view  toward  the  utilization  of  a  very  small  elec- 
•tric  road  as  a  substitute  for  pneumatic  tubes,  constituting  a 
sort  of  forerunner  of  automatic  electric  traction. 

Not  until  the  middle  of  1880  was  any  real  work  in  electric 
railroading  done  in  America.  Mr.  T.  A.  Edison  was,  so  far 
as  experimental  work  goes,  first  in  the  field,  although  in 
projecting  such  a  system  priority  was  awarded  in  the  course 
of  Patent  Office  litigation  to  Stephen  D.  Field,  who  filed  a 
caveat  on  the  subject  May  21,  1879,  and  an  application  for  a 
patent  the  succeeding  March. 

During  the  last  months  of  1878  and  the  first  of  1879  Mr. 
Field  had  been  doing  some  experimentation  on  electric  mo- 
tors, arranging  among  other  things  a  small  electric  hoist; 
but  so  far  as  railroading  is  concerned  his  plans  remained  on 
paper  until  the  latter  part  of  the  year  1880,  a  full  year  after 
the  Siemens  experimental  road  had  been  operating  in  Berlin. 


HISTORICAL   NOTES.  343 

Mr.  Edison,  too,  only  began  work  in  1880,  and  it  was 
June  5  before  he  applied  for  a  patent,  nearly  a  year  after 
the  Siemens  road  was  in  successful  operation,  and  some 
months  after  the  same  distinguished  pioneer  had  been  nego- 
tiating with  the  city  authorities  of  Berlin  for  an  electric  road 
on  a  considerable  scale. 

Edison  laid  down  a  short  experimental  track  near  his  lab- 
oratory at  Menlo  Park,  N.  J.,  and  conducted  some  crude  but 
interesting  experiments;  in  his  first  locomotive  the  power 
was  transmitted  to  the  car  wheels  by  means  of  belts,  and  the 
two  rails  were  utilized  as  conductors. 

The  next  year,  1881,  saw  decided  changes  and  develop- 
ments. Mr.  Field  had  by  that  time  put  a  small  experi- 
mental road  at  Stockbridge,  Mass.,  under  way,  and  Edison 
was  continuing  his  experiments.  Meanwhile  Siemens,  the 
practical  originator  of  modern  electric  traction,  had  not  been 
idle,  and  plans  of  an  elaborate  character — never  realized  in 
their  original  form — were  drawn  up  for  electric  rapid  transit 
in  Berlin.  In  May,  1880,  these  had  taken  shape,  and  were 
in  the  main  for  an  elevated  road  of  a  meter  gauge,  the  rails 
of  which  were  to  form  the  conductors,  while  the  power  was 
to  be  transmitted  from  the  motor  armature  to  the  driving 
wheels  by  means  of  belts.  At  the  same  time  Siemens  was 
drawing  up  plans  for  electric  rapid  transit  express  service 
somewhat  like  that  proposed  in  Paris  some  months  before. 

His  scheme  was  for  an  automatic  electric  road  of  a  little  over 
a  foot  in  gauge  running  completely  incased  in  a  sheet-iron  tube 
of  square  section  about  20  inches  on  a  side.  One  especially 
interesting  feature  of  this  proposition,  which  was  fully  illus- 
trated in  the  Electrotechnische  Zcitsclirift  and  La  Lumiere  Elcc- 
triqne  at  that  time,  was  that  the  armature  of  the  motor  was  to 
be  directly  on  the  axle  of  the  driving  wheels,  much  after  the 
plan  that  is  being  followed  in  the  gearless  motors  of  to-day. 
The  speed  proposed  was  about  40  miles  an  hour,  and  the 
service  was  to  be  entirely  automatic. 

It  was  not  until  the  next  year,  however,  that  the  first  com- 
mercial electric  road  for  regular  service  was  put  into  opera- 
tion. This  was  formally  opened  to  the  public  May  12,  1881, 
at  which  time  the  Lichterfelde  line — which  is  in  operation 


344  THE    ELECTRIC    RAILWAY. 

to-day was  finally  completed.  In  this,  the  third-rail  method 

of  supply  is  employed.  The  construction  of  the  road  was 
begun  in  the  latter  part  of  1880.  This  Lichterfelde  line  was 
the  first  commercial  electric  road,  as  the  little  line  of  1879  at 
Berlin  was  the  first  extensive  experimental  road. 

It  is  worth  noticing  that  July  20,  La  Lumiere  Electrique 
announced  that  the  Lichterfelde  line  had  up  to  that  time 
been  running  without  any  serious  accident,  that  a  company 
for  continuing  it  had  already  been  formed,  and  in  addition, 
that  Siemens  &  Halske  were  just  then  changing  the  horse 
railroad  that  ran  from  Charlottenberg  to  Spandau  into  an 
electric  road.  In  this  installation — to  avoid  some  of  the 
inconveniences  encountered  in  supplying  the  current  through 
the  rails — overhead  wires  were  to  be  used,  to  which  com- 
munication was  made  by  a  trolley  towed  by  the  car. 

The  experimenters  were  then  hesitating  between  the  use 
of  the  double  trolley  line  and  the  single  trolley  using  the 
rails  as  return,  as  practiced  to-day.  A  month  or  two  later, 
at  the  Paris  Exposition,  the  system  of  overhead  supply  was 
used,  in  a  somewhat  different  form,  however,  from  that  just 
mentioned.  The  Siemens  road  exhibited  there  was  \vorked 
on  the  double  trolley  system,  but  the  conductors,  instead  of 
being  wires,  were  a  pair  of  slotted  tubes  in  which  slid  contact- 
makers  connected  to  and  dragged  by  the  car. 

Meanwhile  the  accumulator  had  not  been  forgotten.  In 
1880  a  locomotive  driven  by  accumulators  wras  put  into  oper- 
ation at  the  linen  bleaching  establishment  of  M.  Duchesne- 
Fourmet,  at  Breuil  en  Auge,  the  total  length  of  the  track 
being  over  a  mile.  In  June,  1881,  an  electric  car  operated 
by  accumulators  was  tried  upon  the  Vincennes  tramway  line, 
and  from  about  that  time  the  development  of  accumulator 
traction  went  gradually  on,  both  in  England  and  on  the  Con- 
tinent. 

The  next  noteworthy  electric  road  to  be  put  in  operation 
was  that  at  Portrush,  in  the  north  of  Ireland.  Soon  after  the 
franchises  for  a  tramway  line  over  the  route  had  been  ob- 
tained it  was  suggested  to  Dr.  Werner  Siemens  that  it  was 
a  good  place  for  installing  an  electric  road,  and  work  was  at 
once  begun.  The  line  was  about  6  miles  long.  It  was  com- 


HISTORICAL   NOTES.  345 

pleted  in  the  early  summer  of  1883,  and  the  regular  running 
of  the  trains  began  November  5  of  that  year.  At  the  start 
the  power  was  generated  by  steam,  but  a  pair  of  turbines  was 
soon  installed  at  a  convenient  point  on  the  river  Rush,  1,600 
yards  distant  from  the  nearest  point  on  the  line,  and  for  the 
last  seven  years  the  road  has  been  in  steady  and  successful 
operation.  The  method  of  supply  is  by  a  third  rail. 

Up  to  1883  the  electric  road  in  this  country  was  practically 
undeveloped — all  the  advances  had  been  made  elsewhere;  but 
soon  the  scene  of  activity  was  to  shift.  The  conflicting  inter- 
ests of  Field  and  Edison  were  consolidated  after  a  couple  of 
years  of  litigation,  and  the  Electric  Railway  Company  of  the 
United  States  was  organized  early  in  May,  1883.  The  next 
month  the  Chicago  Railway  Exposition  was  to  open,  and  by 
the  greatest  energy  and  push  an  electric  locomotive  was  con- 
structed and  a  road  laid  around  the  gallery  of  the  main 
building,  the  total  length  being  a  little  over  1,500  feet.  It 
was  of  3-foot  gauge,  and  the  third-rail  method  of  supply  was 
used,  the  two  ordinary  rails  serving  for  the  return.  Auxil- 
iary conductors  were  supplied  to  improve  the  conductivity 
of  the  rails. 

The  road  began  running  early  in  June,  and  after  a  suc- 
cessful career  of  something  less  than  a  month  was  exhibited 
at  the  Louisville  Exposition  during  the  later  part  of  the  same 
year.  By  this  time  American  inventors  had  settled  down  to 
hard  work  on  the  electric  railway  problem,  and  soon  pushed 
on  far  in  advance  of  their  European  competitors. 

In  the  spring  of  1883,  too,  Mr.  C.  J.  Van  Depoele  began 
work  on  electric  traction,  and  laid  down  a  track  about  400 
feet  long,  on  which  a  single  car  was  operated  for  several 
weeks  by  means  of  a  3  horse-power  motor.  Later  in  the  same 
year  a  little  overhead  line  was  constructed  by  Mr.  Van  Depoele 
for  the  Chicago  State  Fair,  and  remained  in  operation  six  or 
seven  weeks. 

Late  in  the  autumn  of  1883  still  another  effort  at  an  electric 
road  was  made  by  Mr.  Leo  Daft.  The  experiments  were  tried 
on  the  Saratoga  and  Mt.  McGregor  Railroad  in  November, 
1883,  and,  as  in  the  case  just  mentioned,  an  electric  locomo- 
tive was  used.  The  motor  was  of  about  12  horse-power,  and 


346  THE    ELECTRIC    RAILWAY. 

its  best  actual  performance  consisted  in  hauling  a  lo-ton 
ordinary  railway  car  loaded  with  68  persons,  at  8  miles  per 
hour,  over  a  track  having  a  grade  of  93  feet  to  the  mile. 
The  current  was  supplied  by  a  third  and  central  rail  composed 
of  iron  rails  of  35  pounds  to  the  yard  laid  on  blocks  of  hard 
wood  saturated  with  resin.  The  current  was  taken  off  this 
rail  by  a  pair  of  phosphor-bronze  contact  wheels  pressed 
lightly  down  upon  the  rail  by  springs.  The  regulation  of 
speed  was  effected  by  commutating  the  field  coils. 

The  next  year,  1884,  saw  still  other  inventors  in  the  field, 
and  before  the  end  of  the  year  considerable  advance  had  been 
made.  During  the  summer  Mr.  Daft  equipped  a  short  line 
on  one  of  the  piers  at  Coney  Island,  which  ran  during  the 
latter  part  of  the  season  and  carried  in  the  aggregate  38,000 
passengers.  At  about  the  same  time,  however,  two  notable 
short  roads  were  opened — one  of  them  on  the  underground 
conduit  principle,  the  other  adopting  the  overhead  trolley 
wire  now  generally  used. 

The  former  road,  installed  in  Cleveland,  Ohio,  by  Bentley 
and  Knight,  was  actually  thrown  open  to  the  public  on 
July  27,  1884,  and  was  the  first  electric  system  to  be  actu- 
ally operated  in  competition  with  horses  on  street  railway 
lines.  The  road  thus  equipped  was  about  two  miles  long. 
The  motor  employed  was  placed  between  the  wheels,  being 
supported  from  the  car  body,  and  connection  to  the  axles 
was  made  by  means  of  wire  cables.  The  slotted  conduit  was 
of  wood  placed  between  the  rails,  and  of  rather  meager  di- 
mensions. The  line  was  operated  with  quite  uniform  success 
for  about  a  year,  when  the  Bentley- Knight  Company  trans- 
ferred its  headquarters  to  Providence,  R.  I. 

A  little  later  in  the  autumn  of  1884  the  first  practical  over- 
head line  on  this  side  of  the  water  was  erected,  the  place 
being  the  suburbs  of  Kansas  City,  Mo. ;  and  the  inventor 
whose  ideas  were  embodied  in  the  short  experimental  road 
of  a  half  mile  in  length  was  Mr.  J.  C.  Henry. 

This  little  road  is  notable  as  embodying  some  radical 
changes  from  previous  methods.  It  was  known  as  the  West- 
port  Electric  Road,  and  was  building  during  the  summer  of 
1884.  The  overhead  line  consisted  of  two  bare,  hard-drawn 


HISTORICAL   NOTES.  347 

copper  wires  supported  from  the  top,  as  is  usually  the  case 
with  all  trolley  wrires  to-day.  The  size  was  No.  i  B.  &  S., 
and  at  that  time  such  hard-drawn  wire  was  only  put  on  the 
market  in  6o-foot  lengths,  so  that  the  experimenters  were 
obliged  to  straighten  it  and  braze  the  joints  on  the  ground. 

The  motive  power  was  supplied  by  a  5  horse-power  Van 
Depoele  motor,  which  was  connected  to  the  car  of  standard 
gauge  by  means  of  differential  gearing  not  unlike  that  used 
on  lathes.  There  were  five  changes  of  speed.  The  motor 
and  gearing  were  supported  together  in  a  frame,  one  end  of 
which  was  connected  to  the  car  axle,  the  other  to  the  car  plat- 
form. There  was  a  bevel  gear  at  the  car  axles  and  a  clutch 
connecting  it  to  the  motor,  so  that  the  armature  could  run 
free  if  necessary. 

Various  experiments  were  tried  in  the  way  of  different 
systems  of  current  supply  and  different  sorts  of  trolleys. 
The  rails  were  temporarily  bonded  by  driving  horseshoe 
nails  between  the  fish  plates  and  the  rails  themselves,  and  in 
some  cases  one  overhead  wire  was  used  merely  as  a  feeder 
for  the  other  and  the  rail  as  return.  The  two  overhead 
wires  were  also  sometimes  used  for  separate  tracks  at  turn- 
outs and  the  rails  again  used  as  a  return.  Various  descrip- 
tions of  trolleys  supported  by  poles,  and  otherwise,  were 
tried,  but  the  form  finally  adopted  was  a  trolley  running  on 
the  line  wires  and  with  contact  wheels  bearing  against  their 
sides,  the  whole  being  connected  to  the  car  by  a  flexible  cable. 

The  generator  was  a  series- wound  dynamo  intended  for 
arc  lighting,  of  10  horse-power  capacity ;  and  the  electromo- 
tive force  was  several  hundred  volts — in  some  of  the  experi- 
ments ;  where  a  dynamo  of  double  the  capacity  was  employed, 
probably  nearly  1,000.  The  steepest  grade  was  7  per  cent., 
and  the  car  was  handled  upon  it  without  any  special  diffi- 
culty. 

A  few  experiments  were  also  tried  with  a  motor  of  double 
the  horse-power,  fitted  on  an  open  street  car,  which  was  used 
for  dragging  a  freight  car  on  a  short  section  of  a  neighboring 
steam  railroad  fitted  up  for  the  purpose.  The  highest  speed 
attained  was  said  to  have  been  at  the  rate  of  20  miles  an  hour. 

This  little  Kansas  City  road  was  a  nearer  approach  to  the 


348  THE    ELECTRIC    RAILWAY. 

forms   familiar   to   us    now   than    anything    that    had    gone 
before  it. 

Unfortunately,  however,  nothing^  important  came  of  the 
experiments,  owing  to  the  difficulty  that  inventors  always 
experience  in  getting  the  public  to  adopt  their  ideas. 

The  fundamental  difficulty  with  the  electric  road  at  that 
time  was  that  it  lacked  public  confidence ;  even  electricians 
turned  up  their  noses  and  looked  askance  at  the  new-fangled 
substitute  for  the  horse.  The  demonstrations  made  on  a 
small  scale  from  time  to  time  were  not  sufficiently  convinc- 
ing, so  that  it  was  an  up-hill  fight  for  those  who  were  pos- 
sessed of  the  courage  of  their  convictions  and  determined  to 
demonstrate  the  practicability  of  electric  traction. 

Nevertheless,  the  work  went  on,  and  in  1885  very  percep- 
tible headway  was  made.  In  the  first  place,  Mr.  Daft,  in  • 
the  early  summer  of  that  year,  equipped  electrically  a  portion 
of  the  lines  of  the  Baltimore  Union  Passenger  Railway  Com- 
pany. The  branch  selected  for  this  purpose  was  that  con- 
nectyig  Hampden  and  Baltimore.  It  includes  considerable 
grades  and  curves,  the  heaviest  grade  being  nearly  7  per 
cent.,  while  the  radii  of  some  of  the  curves  were  as  low  as  50 
feet.  The  system  of  supply  selected  was  the  third  rail,  as 
in  Mr.  Daft's  earlier  roads. 

To  this  end  a  2  5 -pound  T-rail  was  laid  on  special  insulators 
and  formed  the  outgoing  lead,  the  return  being  through  the 
two  outer  rails  together  with  the  ground.  The  electromotive 
force  used  was  but  125  volts,  which  enabled  a  tolerable  degree 
of  insulation  to  be  kept  up.  The  electric  locomotive  contained 
a  single  8  horse-power  motor  weighing  1,000  pounds.  A 
single  gear  reduction  was  employed,  and  the  3 -inch  phosphor- 
bronze  armature  pinion  engaged  an  internal  gear  27  inches 
in  diameter  keyed  on  the  axle  of  the  driving  wheels.  The 
total  weight  of  the  locomotive  was  about  4,200  pounds.  The 
regulation,  as  in  Mr.  Daft's  previous  motors,  was  secured  by 
the  commutated  field  method. 

On  August  8,  1885,  the  road  went  into  operation,  and 
the  original  motors  were  in  service  until  quite  recently. 
Four  electric  locomotives  were  installed  at  various  times 
during  the  first  year  of  operation.  At  street  crossings  the 


HISTORICAL   NOTES.  349 

third  rail  was  abandoned,  and  a  bare  overhead  wire  carried 
the  current,  from  which  it  was  obtained  by  a  trolley  pole 
placed  on  top  of  the  car  much  as  at  present,  carrying  on  its 
end  the  contact  brush. 

About  the  same  time  that  this  road  went  into  operation 
Mr.  Van  Depcele  equipped  a  short  line  at  Toronto,  Canada, 
with  a  single  motor  car  drawing  three  trailers.  Here  an 
overhead  line  was  employed  all  the  way,  the  bare  wire  being 
supported  over  the  car  from  brackets  at  the  side  of  the  track. 
An  underrunning  contact  much  like  that  just  mentioned  in 
connection  with  the  Baltimore  road  was  used. 

Meanwhile  Mr.  F.  J.  Sprague  entered  the  field,  and, 
profiting  by  the  experience  of  others,  spent  a  large  amount 
of  time  in  working  up  the  details  of  electric  traction  ap- 
paratus. His  first  effort  was  the  application  of  electric- 
ity to  the  New  York  Elevated  Railroad  system,  and  in 
December,  1885,  he  publicly  discussed  the  matter.  In  the 
early  part  of  the  succeeding  year  he  was  busily  engaged  on 
the  problem  and  carried  out  an  extensive  series  of  experi- 
ments on  a  section  of  the  elevated  track. 

Though  this  attempt  at  the  elevated  railroad  came  to  noth- 
ing, it  nevertheless  taught  many  a  valuable  lesson  regarding 
the  handling  of  suitable  power  units  and  the  precautions  that 
would  have  to  be  taken  in  railway  work. 

During  1886  and  1887  Mr.  Sprague  was  steadily  at  work  on 
the  electric  traction  problem,  and  the  features  which  he 
brought  into  special  prominence  were  the  method  of  sus- 
pending the  motors  now  generally  used  and  the  development 
of  the  overhead  underrunning  trolley  into  something  like  its 
present  shape.  The  method  of  suspension  employed  was,  as 
is  well  known,  to  pivot  one  end  of  the  motor  directly  upon 
the  car  axle,  sustaining  the  other  by  springs,  so  that  the 
center  of  the  armature  shaft  would  preserve  an  invariable 
distance  from  the  center  of  the  axle,  thereby  securing  the 
proper  meshing  of  the  gears.  At  first  only  a  single  gear 
reduction  was  used,  but  afterward  the  intermediate  shaft 
made  its  appearance,  to  be  displaced  only  in  the  practice  of 
the  last  year. 

This   particular  method  of   support  was  new  in    electric 


350 


THE   ELECTRIC    RAILWAY. 


motors,  although  it  is  said  to  have  been  anticipated  abroad  by 
the  same  method  patented  and  used  for  gas  motors. 

It  was  not  until  almost  the  beginning  of  1888  that  the  first 
Sprague  road  was  actually  put  into  operation — a  small  line 
at  St.  Joseph,  Mo. 

By  January  i,  1888,  there  were  in  operation  in  the  United 
States  and  Canada  13  electric  roads,  operating  95  motor 
cars  over  48  miles  of  track.  They  were  as  follows:  6  Van 
Depoele  roads,  3  Daft,  i  Fisher,  i  Short,  i  Henry,  and  the 
above-mentioned  Sprague  road  at  St.  Joseph,  the  most  ex- 
tensive of  these  being  the  Daft  road  at  Asbury  Park,  N.  J., 
where  eighteen  cars  were  in  operation.  Electricians  had 
not  been  idle,  but  the  electric  road  was  not  yet  fairly 
established. 

During  the  spring  of  1887  the  Union  Passenger  Rail- 
way, of  Richmond,  Va.,  determined  to  adopt  electricity  as  a 
motive  power,  and  Mr.  Sprague  undertook  the  equipment 
of  the  line.  This  was  successfully  accomplished,  and  the 
road  went  into  operation,  after  a  brief  period  of  experi- 
mental use,  early  in  1888.  It  was  the  first  of  the  important 
electric  roads  equipped  in  this  country  or  elsewhere,  and 
gave  an  impetus  to  electric  traction  that  is  unique  even  in 
the  progress  of  this  nineteenth  century. 

Thirteen  miles  of  line  were  equipped,  and  during  the 
spring  of  iSSS,  on  an  average,  20  cars  were  employed. 
There  were  six  4O,ooo-watt,  5oo-volt  Edison  dynamos;  three 
125  horse-power  engines,  and  three  125  horse-power  boilers. 
Although  the  apparatus  was  crude  and  the  road  underwent 
many  vicissitudes,  the  present  success  of  the  electric  road  is 
very  largely  due  to  the  perseverance  and  the  energy  that  put 
the  Richmond  road  in  operation  in  the  face  of  every  sort  of 
discouragement  and  gloomy  prediction  of  failure.  From  that 
time  on  electric  railways  have  grown  in  number  and  size  so 
rapidly  as  to  almost  defy  any  attempt  to  record  them.  Dur- 
ing the  succeeding  year  a  number  of  additional  roads  were 
installed,  and  the  Thomson-Houston  Company,  which  had 
acquired  the  Bentley-Knight  and  Van  Depoele  patents,  en- 
tered the  field. 

Since  that  time  other  electricians  have  been  busy.     The 


HISTORICAL   NOTES.  351 

Sprague  Electric  Railway  and  Motor  Company  came  into  the 
possession  of  the  Edison  General  Electric  Company,  new 
companies  have  arisen,  and  electric  roads  have  been  installed 
so  rapidly  and  in  such  numbers  as  to  occupy  to  the  fullest  the 
resources  of  the  several  companies  that  have  been  engaged 
in  the  work. 

This  brief  record  of  the  history  of  the  electric  railway 
makes  no  claim  to  completeness;  indeed,  a  complete  history 
would  be  hard  to  write  until  the  position  of  the  various 
inventors  shall  be  officially  determined  by  the  courts.  The 
name  of  electric  railway  patents  is  legion,  but  their  value  is 
as  yet  an  indeterminate  quantity — with  a  tendency,  however, 
toward  a  zero  value,  in  view  of  the  early  anticipations  both 
of  some  of  the  most  essential  features  of  modern  electric 
traction  and  the  fact  that  many  of  the  patented  devices  have 
existed  only  upon  paper.  Perhaps  it  has  been  well  for  the 
development  of  this  branch  of  the  electrical  transmission  of 
energy  that  such  is  the  case. 

We  have  made  no  attempt  to  mention  all  those  who  have 
taken  a  part  in  the  development  of  the  electric  railway,  or 
all  the  various  attempts  that  inventors  have  made  to  solve 
the  many  difficulties  that  have  been  encountered.  It  has 
been  our  endeavor,  however,  to  sketch  out,  with  more  atten- 
tion to  general  accuracy  of  perspective  than  to  minuteness  of 
detail,  the  growth  of  the  art  that  has  been  already  productive 
of  such  important  results  and  promises  an  almost  immeasura- 
ble future. 


APPENDIX  A. 


ELECTRIC  RAILWAY  VERSUS  TELEPHONE— DECISIONS 
IN  THE   SUPREME  COURT  OF  OHIO. 

JANUARY   TERM,   1891. 


THE  CINCINNATI   INCLINED   PLANE 
RAILWAY   COMPANY, 

Plaintiff  in  Error, 

against 

THE   CITY   AND    SUBURBAN    TELE- 
GRAPH  ASSOCIATION, 

Defendant  in  Error. 


ELECTRIC  STREET   RAILWAYS — SINGLE-TROLLEY  OVERHEAD  SYSTEM — 
RIGHTS   OF  TELEPHONE  COMPANIES. 

Syllabus. 

1.  The  dominant  purpose  for  which  streets  in  a  municipality  are 
dedicated  and  opened  is  to  facilitate  public  travel  and  transportation, 
and  in  that  view,  new  and  improved  modes  of  conveyance  by  street 
railways  are  by  law  authorized  to  be  constructed,    and  a  franchise 
granted  to  a  telephone  company  of  constructing  and  operating  its  lines 
along  and  upon  such  streets  is  subordinate  to  the  rights  of  the  public 
in  the'streets  for  the  purpose  of  travel  and  transportation. 

2.  The  fact  that  a  telephone  company  acquired  and  entered  upon  the 
exercise  of   a  franchise  to  erect  and  maintain  its  telephone  poles  and 
wires  upon  the  streets  of  a  city,  prior  to  the  operation  of  an  electric 
railway  thereon,  will  not  give  the  telephone  company,  in  the  use  of 
the  streets,  a  right  paramount  to  the  easement  of  the  public  to  adopt 
and  use  the  best  and  most  approved  mode  of  travel  thereon,  and  if  the 
operation  of  the  street  railway  by  electricity  as  the  motive  power  tends 
to  disturb  the  working  of  the  telephone  system,  the  remedy  of  the 
telephone  company  will  be  to  readjust  its  methods  to  meet  the  con- 
dition  created  by  the   introduction  of   electromotive  power  upon  the 
street  railway. 

23  353 


354  THE   ELECTRIC   RAILWAY. 

3.  Where  a  telephone  company,  under  authority  derived  from  the 
statute,  places  its  poles  and  wires  in  the  streets  of  a  municipality,  and 
in  order  to  make  a  complete  electric  circuit  for  the  transmission  of 
telephonic  messages,  uses  the  earth,  or  what  is  known  as  the  "  ground 
circuit,"  fora  return  current  of  electricity,  and  where  an  electric  street 
railway  afterward  constructed  upon  the  same  streets  is  operated 
with  the  "  single-trolley  overhead  system" — so  called — of  which  the 
ground  circuit  is  a  constituent  part,  if  the  use  of  the  ground  circuit  in 
the  operation  of  the  street  railway  interferes  with  telephone  communi- 
cation, the  telephone  company,  as  against  the  street  railway,  will  not 
have  a  vested  interest  and  exclusive  right  in  and  to  the  use  of.  the 
ground  circuit  as  a  part  of  the  telephone  system.  (Decided  Tuesday, 
June  2,  1891.) 

But  it  is  urged  that  the  franchise  of  the  telegraph  association  to 
construct  lines  of  telephone  is  greatly  impaired  by  reason  of  the  single- 
trolley  railway  using  a  grounded  circuit,  whereby  a  large  part  of  the 
electric  current  flows  off  from  the  rails  to  the  surrounding  earth,  and 
to  and  upon  all  telephone  wires  which  may  be  connected  with  the 
earth  in  proximity  to  the  railway.  The  action  is  described  as  conduc- 
tion, causing  more  or  less  of  electric  current  to  be  poured  into  the 
earth  and  into  all  electric  conductors  connected  with  the  earth,  thereby 
reaching  telephone  wires  in  a  grounded  circuit,  and  creating  loud  and 
continuous  noises  upon  the  wires,  which  disturb  telephonic  communi- 
cation. This  disturbance,  however,  results  not  solely  from  the  earth 
circuit  of  the  railway  company,  but  also  from  the  fact  that  the  defend- 
ant in  error  likewise  relies  upon  the  earth  for  its  return  circuit,  by 
connecting  with  the  earth  the  end  of  its  wire  furthest  from  its  electric 
batteries. 

It  is  claimed  that  in  addition  to  this  conduction  or  leakage  disturb- 
ance the  single-trolley  electric  railway  introduces  serious  disturb- 
ances on  telephone  lines  by  induction,  for  the  reason  that  such  electric 
railways  employ  large  wires  to  convey  the  current  used  for  the  pro- 
pulsion of  their  cars,  and  this  current  is  constantly  and  rapidly  chang- 
ing its  strength ;  that  these  rapidly  changing  currents  in  the  electric 
railway  wires  induce  disturbing  currents  in  parallel  telephone  wires 
near  which  the  electric  railways  have  been  built,  and  thus  prevent  a 
successful  transmission  of  telephonic  messages. 

These  interferences  with  the  telephone  service  may  be  obviated, 
it  is  stated,  by  the  railway  company  giving  up  the  single-trolley  system 
with  the  ground  circuit,  and  substituting  the  double-trolley  system 
with  its  two  trolley  wires,  two  trolley  wheels,  and  electric  current 
passing  from  one  wire  through  one  trolley,  through  the  motor,  back 
through  the  other  trolley  to  the  other  wire,  and  so  back  to  the  genera- 
tor, without  escaping  to  the  earth.  The  grounded  circuit,  it  is  insisted, 
should  be  abandoned  and  surrendered  to  the  sole  use  and  service  of 
the  defendant  in  error.  But  it  is  admitted  that  other  remedies  of 


APPENDIX    A. 


355 


the  telephone  disturbances  may  be  easily  obtained  by  constructing  the 
telephone  with  a  complete  metallic  circuit,  or  by  resort  to  what  is 
known  as  the  McCluer  device,  consisting  of  a  single  return  wire,  to 
which  a  number  of  telephone  wires  are  attached. 

Conceding  that  the  mode  adopted  by  the  railway  company  of  pro- 
pelling its  cars  by  electricity  is  an  interruption  to  the  telephone  service 
of  the  defendant  in  error  and  calculated  to  impair  its  franchise  in  the 
manner  contended,  the  inquiry  is  suggested  whether  the  railway  com- 
pany must  yield  up  a  useful  franchise  that  the  same  may  be  exclusively 
enjoyed  by  the  telegraph  association,  or  whether  the  association  shall 
adapt  its  system  to  existing  conditions ;  whether  the  company  shall 
change  from  the  single  to  the  double  trolley  system,  from  the 
grounded  to  the  metallic  circuit,  or  whether  the  association  shall 
either  use  a  complete  metallic  circuit  or  resort  to  the  McCluer  device. 

It  is  immaterial  on  which  party  the  expense  of  the  change  may  fall 
the  more  heavily.  It  is  a  question  of  legal  right. 

When  the  telegraph  association  erected  its  poles  and  lines  in  1881 
and  1882,  with  the  design  of  conducting  the  business  of  a  telephone 
company,  it  found  the  railway  company  operating  its  street  railway, 
with  authority  under  the  statute  to  use  other  motive  power  than  ani- 
mals, to  wit,  electricity,  cable,  or  compressed  air,  upon  obtaining  the 
consent  of  the  Board  of  Public  Works.  The  telephone  business  was  not 
among  the  probabilities  when  the  streets  of  Cincinnati  now  made  use 
of  by  the  telegraph  association  were  dedicated  or  condemned  for  the 
public  use.  The  primary  and  dominant  purpose  of  their  establishment 
was  to  facilitate  travel  and  transportation ;  they  belong  from  side  to 
side  and  end  to  end  to  the  public,  that  the  public  may  enjoy  the  right 
of  traveling  and  transporting  their  goods  over  them.  The  telephone 
poles  and  wires  and  other  appliances  are  not  among  the  original  and 
primary  objects  for  which  streets  are  opened,  for  they  may  be  placed 
elsewhere  than  on  the  highways  and  yet  accomplish  their  purpose. 
In  Taggart  v.  Street  Railway  Co.,  16  R.  L,  it  was  said  by  Durfee,  C.  J., 
that  telephone  poles  and  wires  are  not  used  to  facilitate  the  use  of 
the  streets  for  travel  and  transportation ;  "  whereas  the  poles  and 
wires  of  the  railway  company  are  directly  ancillary  to  the  use  of  the 
streets  as  such,  in  that  they  communicate  the  power  by  which  the 
street  cars  are  propelled."  As  a  general  rule,  an  occupation  of  the 
streets  otherwise  than  for  travel  and  transportation  is  presumptively 
inferior  and  subservient  to  the  dominant  easement  of  the  public  for 
highway  purposes,  for  if  not  so,  the  primary  object  of  their  dedication 
or  appropriation  might  be  largely  defeated.  And  the  fact  that  per- 
mission is  granted  to  occupy  the  streets  or  highways  for  a  purpose 
other  than  travel,  does  not  confer  a  prior  and  paramount  right  to 
occupy  them  to  the  exclusion  of  their  use  for  travel  in  a  mode  different 
from  what  obtained  when  such  permission  was  given. 

To  those  improved  agencies,  devised  for  the  convenience  and  ad- 


356     '  THE   ELECTRIC   RAILWAY. 

vantage  of  the  community  in  general,  the  franchise  of  the  telephone 
company  to  occupy  the  streets  for  carrying  on  its  business  must  be 
secondary  and  subordinate.  Whether  all  who  go  upon  the  streets  shall 
have  the  most  convenient  and  expeditious  passage  and  carriage  of 
person  and  goods,  has  not  been  made  dependent  upon  the  manner  in 
which  the  defendant  in  error  has  preferred  to  locate  its  poles,  stretch 
its  telephone  wires,  or  form  the  electric  circuit. 

It  is  in  recognition  and  maintenance  of  the  superior  easement  of  the 
public  in  the  streets  that  city  councils  are  required  to  "  cause  the  same 
to  be  kept  open  and  in  repair  and  free  from  nuisance ;"  that  the  streets 
are  graded  and  paved  and  proper  regulations  of  police  provided  to 
govern  the  actions  of  persons  using  them ;  that  the  abutting  owner, 
though  having  a  peculiar  interest  and  easement  in  the  adjacent  street 
appendant  to  his  lot,  has  no  right  to  place  permanent  obstructions  in 
the  street,  nor  do  any  act  on  his  own  land  outside  the  limits  of  the 
street,  that  will  make  the  way  inconvenient  or  hazardous  or  less  secure 
than  it  was  left  by  the  municipal  authorities. 

This  paramount  easement  or  estate  which  the  public  acquires  in  the 
streets,  carrying  with  it  a  special  interest  in  the  adoption  of  the  most 
approved  systems  of  modern  street  travel,  cannot  be  made  subservient 
to  the  telegraph  or  telephone  when  admitted  on  the  highway,  without 
the  clearest  expression  of  the  legislative  will. 

The  demand  made  by  the  telegraph  association  is,  not  that  the  rail- 
way company  shall  so  modify  its  existing  electrical  apparatus  as  not 
to  interfere  with  the  telephone  service,  but  shall  forever  abandon  the 
use  of  an  essential  part  of  its  electromotive  system,  or  be  perpetually 
enjoined.  In  other  words,  the  association  claims  the  exclusive  use  of 
the  grounded  circuit,  inasmuch  as  the  mechanism  of  the  telephone  is. 
so  complex  and  the  electric  currents  employed  so  delicate  and  sensitive 
that  they  cannot  be  used  without  disturbance  from  the  heavier  cur- 
rents employed  by  neighboring  electrical  enterprises  that  operate  with 
the  grounded  circuit.  We  find  no  foundation  for  such  an  exclusive 
franchise  or  right. 

When  the  telegraph  association  began  its  operations  under  the  tele- 
phone system,  neither  the  statute  authorizing  it  to  erect  and  maintain 
poles,  wires  and  other  necessary  fixtures,  nor  the  ordinance  under 
which  it  obtained  the  power  to  extend  its  lines  in  the  streets,  gave  an 
exclusive  right  either  to  use  the  earth  for  a  return  circuit  or  a  com- 
plete metallic  circuit  formed  by  double  wires.  The  Legislature  did  not 
grant  the  right  by  general  enactment,  nor  was  the  municipal  corpora- 
tion empowered  by  the  Legislature  to  give  the  telegraph  association 
the  exclusive  right  to  make  use  of  its  streets  so  as  to  create  a  monopoly. 

It  is  contended,  however,  that  the  defendant  in  error,  by  virtue  of 
its  grants,  acquired,  before  the  railway  company  had  a  right  to  use 
electricity  as  a  motive  power,  a  vested  interest  in  the  telephone  sys- 
tem as  it  now  operates  it,  with  a  grounded  circuit,  and  that  not  even 


APPENDIX   A.  357 

the  Legislature  of  the  State  could  take  away  from  it  or  injure  this  fran- 
chise, on  the  faith  of  which  it  has  expended  its  capital  and  labor. 
Special  privileges  or  immunities  are  under  the  control  of  the  Legislat- 
ure. If  granted  they  may  be  altered,  revoked,  or  repealed  by  the 
General  Assembly.  Art.  i,  Sec.  2  of  the  Constitution.  And  while  cor- 
porations with  valuable  franchises  may  be  formed  under  general  laws, 
all  such  laws  may,  from  time  to  time,  be  altered  or  repealed.  Consti- 
tution, Art.  13,  Sec.  2.  In  view  of  these  constitutional  provisions,  it  is 
clearly  within  the  power  of  the  General  Assembly  to  authorize  one 
class  of  corporations  to  use,  in  the  streets,  electricity  with  the 
grounded  circuit  as  a  motive  power,  and  another  class  to  employ  the 
same  or  a  similar  agency  for  the  transmission  of  telegraphic  or  tele- 
phonic messages.  And  if  the  proper  exercise  of  the  rights  granted  to 
the  one  class  under  general  law  is  irreconcilable  and  plainly  interferes 
with  a  prior  grant  to  a  corporation  of  the  other  class,  it  may  be  con- 
strued as  the  intention  of  the  Legislature  to  deny  an  exclusive  fran- 
chise, if  not  to  repeal  the  antecedent  grant. 

It  is  contended,  however,  in  behalf  of  the  defendant  in  error,  that 
conceding  the  railway  company  and  telegraph  association  to  be  upon 
an  equal  footing  on  the  streets  and  highways  in  the  enjoyment  of  their 
respective  franchises,  the  company  is  bound  to  conform  to  the  rule  sic 
utere  tuo  ut  alienum  non  laedas.  In  the  view  which  we  take  of  the  rela- 
tion to  each  other  of  the  parties  to  the  action,  we  deem  it  unnecessary 
to  inquire  whether  there  has  been  a  want  of  conformity,  and  to  what 
extent,  if  any,  on  the  part  of  the  railway  company,  to  the  requirements 
of  the  legal  maxim.  Nor  do  we  think  it  necessary  to  determine  how 
far  an  incorporated  company  making  a  lawful  and  careful  use  of  its 
own  property,  or  of  a  franchise  granted  to  it  by  the  proper  municipal 
authorities,  may  be  held  liable  for  damages  incidentally  caused  to 
another. 

From  the  undisputed  facts  in  the  case,  as  disclosed  in  the  record  and 
printed  arguments  of  counsel,  it  is  evident,  as  we  have  already  seen, 
that  the  railway  company  acquired  from  the  State  and  from  the  city  of 
Cincinnati  authority  to  erect  and  maintain  poles  and  wires  in  the 
streets  or  highways,  and  to  use  electricity  as  a  motive  power  for  its 
cars.  Clothed  with  such  authority,  we  have,  upon  weighing  the- alle- 
gations .in  the  original  petition  and  applying  to  them  the  well-settled 
principles  governing  the  legal  rights  of  the  pfcblic  in  the  highways, 
reached  the  conclusion  that  the  facts  set  forth  in  the  petition  are  not 
sufficient  to  constitute  a  cause  of  action.  We  are  of  the  opinion  that 
there  has  been  no  invasion  of  the  rights  of  the  telegraph  association 
by  the  plaintiff  in  error,  and  that  the  telegraph  association  is  not  en- 
titled to  the  relief  prayed  for  in  its  petition.  The  judgment,  therefore, 
of  the  Superior  Court  at  general  and  special  term  must  be  reversed 
and  the  original  petition  dismissed.  Judgment  accordingly. 


THE   ELECTRIC    RAILWAY. 


SUPERIOR   COURT   OF   CINCINNATI. 


THE   CITY   AND    SUBURBAN    TELE- 
GRAPH  ASSOCIATION 


THE  CINCINNATI   INCLINED   PLANE 
RAILWAY   COMPANY. 


Taft,  J. — This  is  an  action  to  enjoin  the  defendant  from  using  a  sys- 
tem of  electric  railway  propulsion,  known  as  the  single-trolley  system, 
in  running  its  cars  upon  the  streets  of  this  city  and  the  roads  of  the 
county,  because,  as  plaintiff  claims,  it  does  a  great  injury  to  the  con- 
duct of  the  public  business  in  which  it  is  engaged — i.e.,  the  maintenance 
for  profit  of  telephone  communication  between  a  large  number  of 
subscribers  in  the  city  and  county. 

Plaintiff  alleges  that  it  has  been  conducting  its  business  under  lawful 
grants  of  the  Legislature  of  the  State  and  the  municipal  authorities, 
and  by  virtue  thereof  has  lawfully  erected  many  lines  of  telephone 
wires  on  the  streets  upon  which  the  street  railway  of  defendant  is 
constructed  and  operated ;  that  the  defendant  has  no  lawful  authority 
to  use  electricity  as  a  propulsive  power  for  its  cars ;  that  the  single- 
trolley  system  in  use  by  defendant  conducts  upon  and  induces  upon 
the  wires  of  the  plaintiff  erected  on  the  same  streets  currents  of  elec- 
tricity, which  makes  it  impossible  to  use  those  wires  for  the  purpose 
of  telephone  communication ;  that  the  result  is  that  many  of  the  sub- 
scribers of  plaintiff  have  made  complaint  and  threatened  to  discontinue 
the  use  of  the  telephone,  and  some  have  refused  to  continue  payment 
for  the  same,  all  to  the  great  injury  of  the  plaintiff ,  that  the  damage 
is  irreparable  and  continuous,  and  that  plaintiff  notified  defendant  be- 
fore the  erection  of  the  single-trolley  system  that  it  would  result  in  a 
serious  injury  to  plaintiff,  and  of  the  objection  to  the  system. 

The  defendant  answers,  denying  plaintiff's  lawful  right  to. operate 
telephone  lines;  avers  its  own  lawful  right  to  conduct  a  system  of 
electrical  railway  propulsion ;  avers  that  the  single-trolley  system  is 
the  only  practicable  one  in  use  and  secures  advantages  to  the  defendant 
not  afforded  by  any  other;  that  plaintiff's  difficulties  arise  from  the 
defects  of  its  own  telephone  system,  in  that,  for  economy,  it  uses  the 
earth  as  a  return  conductor,  and  so  invites  onto  its  lines  many  disturb- 
ing currents,  both  natural  and  artificial,  although  the  mechanism  of 
the  telephone  is  so  delicate  that  any  proper  system  would  make  the 
return  circuit  metallic;  that  plaintiff's  claim  amounts  to  a  claim  to 


APPENDIX   A.  359 

\ 

the  exclusive  use  of  the  earth  as  a  conductor,  which  is  without  war- 
rant of  law ;  that  the  use  by  the  defendant  of  the  earth  as  a  return 
circuit  is  a  material  assistance  in  propelling  cars  up  heavy  grades; 
that  it  could  not  alter  its  system  so  as  to  avoid  the  use  of  the  earth  as 
a  return  circuit  except  at  great  outlay  and  loss  of  efficiency.  The 
answer  denies  that  the  operation  of  its  road  produces  interference 
with  the  telephone  lines  of  plaintiff,  and  says  that  if  any  injury  has 
been  produced  for  which  defendant  is  liable,  the  damages  are  capable 
of  exact  ascertainment,  because  they  can  all  be  remedied  by  an  addi- 
tional expenditure  by  the  plaintiff,  and  that  therefore  there  is  no 
ground  for  equitable  relief. 

Th^re  can  be  no  doubt  that' the  plaintiff  has  a  lawful  right  to  occupy 
the  streets  upon  which  defendant's  track  is  laid,  with  the  poles  and 
wires  erected  for  the  conduct  of  its  business,  and  that  the  use  of  the 
earth  as  a  return  is  not  a  violation  of  its  franchise.  It  was  organized  as 
and  still  is  called  a  telegraph  company.  It  began  its  telephone  busi- 
ness before  Section  3,471  was  passed,  and  perhaps  some  of  its  poles  and 
lines  along  the  streets  occupied  by  defendant  were  erected  for  such 
use.  But  this  circumstance  is  immaterial,  for  it  has  been  held,  both 
in  England  and  in  this  country,  that  the  telephone  system,  which  is 
communication  over  long  and  short  distances  through  the  agency  of 
currents  of  electricity  on  metal  wires,  is  really  a  magnetic-telegraph 
system,  and  that  an  exclusive  right  to  operate  the  telegraph  includes 
the  exclusive  right  to  operate  telephone  lines.  Attorney  General  v, 
Edison  Telephone  Co.,  6  Q.  B.  D. ,  244;  Wisconsin  Tel.  Co.  v.  Oshkosh, 
62  Wis.,  32. 

Having  determined,  then,  that  plaintiff's  use  of  the  streets  on  which 
defendant  operates  its  road  is  lawful,  the  next  question  which  arises 
is  whether  defendant  has  the  right  to  use  electricity  for  the  propulsion 
of  its  cars.  If  it  has  not  and  it  thereby  interferes  with  plaintiff's 
franchise,  it  is  very  clear  that  such  interference  gives  plaintiff  a  right 
of  action. 

On  the  whole,  then,  I  am  of  opinion  that  the  Legislature  conferred 
the  right  upon  defendant  to  use  any  other  motive  power  than  animal 
whenever  the  Board  of  Public  Works  should  consent.  Now,  the  board 
did  consent,  on  October  24,  1885,  that  defendant  should  use  either  a 
cable,  compressed  air,  or  electricity.  It  has  chosen  electricity,  and 
has  produced  the  necessary  authority  to  erect  its  poles  and  string  its 
wires. 

Such  being  the  condition  of  the  franchises  which  the  plaintiff  and 
defendant  are  lawfully  entitled  to  enjoy,  considered  each  without  ref- 
erence to  the  other,  it  becomes  necessary  to  inquire,  first,  whether  any 
loss  has  been  inflicted  upon  plaintiff  by  defendant,  and  if  so,  how  has 
it  occurred ;  second,  whether  such  loss,  if  any,  is  justified  by  defend- 
ant's franchise,  so  as  to  be  damnum  absque  injuria,  which  involves  the 
preliminary  question  whether  the  Legislature,  after  having  given  the 


56o  THE    ELECTRIC    RAILWAY. 

plaintiff  the  right  to  construct  its  telephone  system,  on  the  faith  of 
which  right  it  has  expended  large  amounts,  can  confer  a  franchise  on 
another,  the  exercise  of  which  will  seriously  impair  the  plaintiff's 
franchise  as  heretofore  enjoyed. 

First,  a  current  of  electricity  cannot  be  produced  without  a  circuit — 
that  is,  unless  the  negative  and  positive  poles  of  the  generating  battery 
or  instrument  are  connected  by  a  continuous  substance  capable  of 
conducting  the  current.  Such  a  substance  may  be  a  metal  wire,  or 
if  both  poles  of  the  battery  be  connected  with  the  earth  by  metal 
wires  the  current  will  find  a  circuit  through  the  wires  and  the  earth. 
The  earth,  by  reason  of  its  immense  mass,  makes  an  excellent  con- 
ductor. By  what  paths  the  current  discharged  into  it  over  the  wire 
from  one  pole  finds  its  way  throughout  to  the  wire  from  the  other  pole 
is  not  capable  of  determination. 

The  telephone  is  a  mechanism  by  which  the  sound  of  human  speech 
is  reproduced  over  long  distances.  Without  attempting  to  describe  the 
exact  mode  in  which  this  result  is  brought  about,  I  may  say  that  the 
sound  waves  of  the  human  voice  produce  vibrations  in  a  thin  ferrotype 
plate,  which,  by  means  of  a  magnet  and  an  induction  coil,  are  con- 
verted into  corresponding  vibrations  in  an  electric  current  on  the  con- 
necting wire,  and  these  vibrations  are,  in  turn,  by  means  of  the 
inducing  coil  and  magnet  at  the  other  end,  converted  into  exactly 
corresponding  vibrations  on  a  plate  there,  reproducing  the  sound 
waves  of  the  voice  of  the  speaker  in  such  a  manner  as  to  enable  the 
receiver  to  understand.  The  current  on  the  connecting  wire  is  a 
slight  one,  and  the  circuit  is  completed,  not  by  a  return  wire,  but  by 
a  ground  wire  brought  into  contact  with  the  earth.  This  contact  is 
usually  made  by  attaching  the  wire  from  the  negative  pole  of  the 
single  cell  battery  in  each  telephone  to  a  gas  pipe  or  water  pipe 
running  down  into  the  earth. 

In  the  Sprague  system  of  electric  railways,  which  is  the  kind  used 
by  the  defendant,  the  electricity  used  to  operate  the  motors  under  the 
cars  is  conveyed  to  them  by  a  single  overhead  wire  suspended  over 
the  middle  of  the  track,  along  the  under  side  of  which  runs  a  trolley 
wheel  on  a  single  mast  attached  to  the  car,  making  electric  connection 
between  the  overhead  wire  and  the  motor  of  the  car,  and  allowing  the 
current  to  pass  down  through  the  motor  and  onto  the  track,  whence 
some  of  it  returns  directly  to  the  dynamo  generator  at  the  power 
house.  A  large  part  of  the  electricity  leaves  the  track,  however,  and 
by  other  and  various  paths  also  finds  its  way  through  the  earth  back 
to  the  dynamo. 

In  addition  to  the  overhead  trolley  wire,  which  is  supported  by  guide 
wires  from  iron  posts  erected  on  the  curb  at  regular  intervals,  there 
is  what  is  called  a  feed  wire  strung  along  on  these  posts  for  the  pur- 
pose of  keeping  up  the  required  quantity  of  electricity  on  the  trolley 
wires.  On  the  streets  where  are  telephone  wires  and  electric  railway 


APPENDIX   A.  361 

wires  their  general  course  must  be  parallel.  The  evidence  in  the 
case  establishes  beyond  a  doubt  that  since  the  defendant  began  the 
operation  of  its  line  by  electricity  in  June,  1889,  down  to  the  time  of 
trial,  the  usefulness  of  all  the  telephones  along  the  line  of  the  railway 
has  been  more  or  less  impaired;  that  in  many  cases  the  buzzing 
noise  which  seems  to  be  the  chief  form  of  the  disturbance  has  been 
so  loud  and  continuous  that  communication  over  the  lines  has  been 
impossible.  Nor  has  the  disturbance  been  confined  to  telephones  on 
the  line  of  the  railway.  Telephones  several  miles  from  the  city  whose 
connecting  lines  ran  parallel  for  any  distance  with  the  railway  were 
similarly  affected  and  the  buzzing  noise  in  many  of  these  seems  to 
have  been  quite  as  deafening  as  in  telephones  along  the  line.  Alto- 
gether more  than  two  hundred  lines  have  been  affected  in  this  way,  to 
a  greater  or  less  degree.  The  cause  of  the  trouble  is  undoubtedly 
the  operation  of  the  electric  railways,  and  the  way  by  which  it  is 
brought  about  is  twofold.  First,  the  escape  of  the  electric  fluid  from 
the  rails,  which  is  called  earth  distribution  or  leakage,  near  where  the 
wire  from  the  telephone  is  connected  with  the  earth,  brings  upon  this 
earth-connection  wire  of  the  telephone  varying  currents  of  electricity 
of  much  greater  quantity  than  that  necessary  for  the  telephone  current, 
and  produces  upon  the  magnet  and  inducing  coil  an  effect  which  results 
in  vibrations  of  a  very  different  character  from  those  produced  by  the 
.  human  voice,  and  makes  a  noise  like  the  buzzing  of  a  saw.  Second,  a 
similar  noise  is  made  by  induction.  It  is  a  physical  fact  of  much  im- 
portance in  electric  mechanism  that  where  two  wires  of  two  circuits 
are  parallel  to  each  other,  and  there  is  a  current  of  varying  intensity 
on  one  of  them,  this  will  produce  in  the  other,  in  the  opposite  direc- 
tion, a  current  of  electricity  of  similar  variation.  The  insulation  of 
the  wires  has  no  effect  to  reduce  the  current  produced  in  this  way. 
The  amount  of  induction  depends  upon  variation  in  the  current,  the 
distance  of  the  wires  from  each  other,  and  the  length  of  the  parallelism 
of  the  wires.  The  current  upon  the  trolley  wire  and  the  feed  wire  of 
the  railway  is  quite  variable  in  quantity  and  intensity,  owing  to  the 
drain  upon  the  store  of  electricity  by  the  moving  and  stopping  of  the 
car.  Nor  is  the  electricity,  as  generated,  exactly  uniform  in  its  flow 
from  the  dynamo.  The  result  is  that  wherever  the  telephone  wire 
is  parallel  with  the  trolley  wire  and  the  feed  wire,  there  is  induced 
upon  the  telephone  wire  a  current  whose  variations  correspond  with 
the  variations  of  the  electrical  current  on  the  electric  railway  wires, 
and  this,  acting  upon  the  inducing  coil  and  magnet,  produces  vibra- 
tions of  the  pin  plate,  which  makes  the  buzzing  sound.  It  is  not  possi- 
ble, in  listening  to  the  sounds  produced  by  the  electric  railway,  to 
say  whether  it  is  the  result  of  induction  or  earth  leakage.  Some  of 
plaintiff's  subscribers,  notably  Proctor  &  Gamble,  have  loud  buzzing 
sounds  upon  their  telephones,  the  ground  wires  of  which  are  at  such  a 
distance  from  the  railway  track  as  to  make  it  quite  unlikely  that  the 


362  THE    ELECTRIC    RAILWAY. 

disturbance  could  have  been  caused  by  earth  leakage,  while,  on  the 
other  hand,  their  wires  are  for  some  distance  parallel  with  the  trolley 
and  feed  wire  of  the  railway  company.  Other  telephones  are  dis- 
turbed on  the  line  of  the  road,  though  their  wires  are  not  parallel  with 
the  trolley  wire.  Expert  evidence  attributed  the  disturbance  about  one- 
half  to  induction  and  one-half  to  conduction  or  earth  leakage.  This, 
of  course,  is  only  a  rough  estimate,  and  the  fact  may  vary  much  in 
particular  instances.  The  injury  to  plaintiff's  service  is  produced,  then, 
speaking  in  a  general  way,  one-half  by  the  defendant  pouring  elec- 
tricity into  the  earth,  which  finds  its  way  into  the  property  of  plain- 
tiff's subscribers,  and  thence  into  the  wire  of  the  telephone,  and  one- 
half  by  a  creation  of  a  current  on  plaintiff's  wires  in  the  street  by  the 
parallelism  of  defendant's  wire  and  the  varying  character  of  the  cur- 
rent. The  result  has  been  a  very  substantial  interference  with  the 
plaintiff's  business,  and  if  the  present  condition  continues  it  will 
end  in  a  serious  loss. 

Is  it  a  loss  for  which  defendant  is  liable?  The  contention  on  behalf 
of  the  defendant  is  that  because  it  has  full  power  to  operate  by  elec- 
tricity under  the  law,  the  loss  resulting  to  the  plaintiff  is  dammun 
absque  injuria,  and  if  the  plaintiff  wishes  to  avoid  the  loss,  it  must 
adopt  safeguards  in  the  shape  of  a  metallic  circuit  to  avoid  the  diffi- 
culty. To  this  plaintiff  replies  that  by  virtue  of  its  grants  it  ac- 
quired, before  the  defendant  had  a  right  to  use  electricity  as  a  motive, 
power,  a  vested  interest  in  the  telephone  system  as  it  now  operates  it, 
with  a  grounded  circuit,  and  that  not  even  the  Legislature  of  the  State 
could  take  away  from  it  or  injure  this  franchise,  on  the  faith  of  which 
it  has  expended  so  much  capital  and  labor. 

I  am  inclined  to  think  that  under  the  constitutional  provision  that 
all  laws  for  the  forming  of  corporations  may  be  altered  or  repealed 
(Sec.  2,  Art.  13),  it  would  be  in  the  power  of  the  Legislature  to  grant 
a  right  to  other  corporations  for  a  public  use  to  so  use  the  street  as  to 
require  the  plaintiff  company,  if  it  wished  to  continue  in  the  telephone 
business,  to  change  its  system,  and  that  without  any  right  of  action 
against  such  corporations.  The  case  of  Ry.  Co.  r.  Ry.  Co.,  30  Ohio 
St.,  604,  shows  that  where  one  railway  company  condemned  a  right  of 
way  across  the  track  of  another,  that  other  cannot  recover  for  an 
injury  to  its  franchise  as  a  railroad  or  for  the  increased  expense  en- 
tailed upon  it  in  obeying  the  laws  of  the  State  with  reference  to  rail- 
road crossings.  However  this  may  be,  I  am  very  clear  that  no  intention 
on  the  part  of  the  Legislature  to  abridge  the  granted  rights  of  one  cor- 
poration by  a  new  grant  to  another  will  be  recognized  by  the  courts 
unless  such  intention  plainly  appears  in  the  law.  In  England,  the 
power  of  Parliament  is  unlimited,  and  it  may  even  confiscate  private 
property,  and  a  fortiori  may  abridge  and  destroy  chartered  rights  and 
franchises.  •  Nevertheless,  we  find  in  that  country  that  where  one  cor- 
poration is  granted  a  right  which  may  be  so  exercised  as  to  injure  or 


APPENDIX   A.  363 

interfere  with  a  right  previously  granted  to  another,  the  presumption 
of  law  is  that  Parliament  intended  only  such  uses  as  were  consistent 
with  the  rights  of  the  first  corporation.  In  Gas  Light  and  Coke  Co.  v. 
Vestry,  15  Q.  B.  D.,  i,  plaintiff  was  a  gas  company  which  had  laid  its 
gas  pipes,  by  virtue  of  a  public  grant,  under  a  street  which  the  defend- 
ant, a  public  corporation,  was  charged  with  keeping  in  repair,  and 
upon  which  it  used  such  heavy  rollers  as  to  injure  the  pipes  of  the 
plaintiff.  The  rolls  used  were  economical  and  well  fitted  for  the  pur- 
pose, but  it  was  held  that  unless  the  defendants  were  expressly 
authorized  by  statute  to  use  rollers  of  the  size  and  weight  of  those 
which  did  the  injury,  the  defendant  could  not  justify  under  a  duty  to 
keep  in  repair  which  might  be  discharged  by  rollers  of  less  weight 
and  without  breaking  the  pipes. 

This  case  is  peculiarly  applicable  to  the  case  at  bar,  because  here 
was  a  case  of  a  public  grant  to  the  gas  company  enjoyed  in  a  certain 
way,  followed  by  a  grant  to  the  defendant  to  exercise  another  right, 
which,  if  exercised  in  one  way,  would  injure  plaintiff's  enjoyment  of 
its  right,  and  which,  if  exercised  in  another,  would  not.  The  same 
principle  is  here  applied  that  courts  recognize  wherever  private  prop- 
erty is  injured  by  the  exercise  of  authority  granted  by  the  Parliament. 
See  Hammersmith,  etc.,  Ry.  Co.  v.  Brand,  L.  R.  4  H.  L.,  171 ;  Queen 
v.  Bradford  Navigation  Co.,  6  B.  &  S.,  631  ;  Geddis  v.  Proprietors  of 
Bann  Reservoir,  3  App.  Cases,  430;  Att'y  Gen'l  r.  Colney  Hatch  Lu- 
natic Asylum,  L.  R.  4  Ch.  App.,  416;  Att'y  Gen'l  r.  Gas  Light  and  Coke 
Co.,  7  Ch.  D.,  217;  Managers  Metrop.  Asylum  District  v.  Hill,  6  App. 
Cases,  193. 

Even,  then,  if  franchises  to  occupy  the  public  streets  conferred  by  the 
Legislature  may  be  subject  to  modifications  of  their  use  and  enjoyment 
by  other  public  grants  of  the  Legislature,  it  is  certain  that  unless  the 
legislative  intent  to  make  such  modification  clearly  appears,  either  by 
express  words  or  by  necessary  implication  arising  from  the  impossibil- 
ity of  enjoying  the  second  grant  without  such  modification,  it  will  not 
be  inferred. 

But  it  is  said  that  this  principle  can  have  no  place  here  because  the 
right  to  occupy  the  street  for  the  purpose  of  travel  is  a  superior  right 
to  that  of  using  it  for  the  telephone  poles.  Defendant's  counsel,  to 
establish  this,  rely  on  The  Spring  Grove  Ave.  v.  Cumminsville,  14 
Ohio  St. :  Smith?'.  Tel.  Co.,  2  C.  C.  R.,  259;  Mt.  Adams  &  E.  P.  R.  Co.  v. 
Winslow,  3  C.  C.  R.,  425;  R.  R.  Co.  v.  Williams,  35  Ohio  St.,  171; 
Pike's  Ex'rs  v.  Western  U.  Tel.  Co.,  decided  by  this  Court. 

These  cases  have  no  bearing  upon  this  case  at  all,  as  it  seems  to  me. 
They  involved  a  discussion  of  whether  the  erection  of  certain  struct- 
ures in  the  street  could  be  considered  a  new  burden  and  use,  not 
included  in  the  easement  which  the  abutting  property  holder  had 
originally  granted  to  the  public,  and  whether  therefore  he  was  entitled 
to  compensation.  It  is  unquestionably  within  the  power  of  the  Legis- 


264  THE    ELECTRIC    RAILWAY. 

lature,  so  far  as  the  public  is  concerned,  to  enlarge  the  benefit  to  be 
derived  from  the  streets,  so  as  to  include  other  public  purposes  than 
those  of  mere  travel  (Ry.  Co.  v.  Lawrence,  38  Ohio  St.,  45).  If  this 
takes  more  from  the  abutting  property  holder  than  he  originally  gave, 
then  he  may  have  compensation,  but  the  public  cannot  complain,  for 
their  representative,  the  Legislature,  has  spoken  and  granted  the  use. 
When  the  telephone  company  is  granted  the  right  to  use  the  streets, 
its  right  is  as  well  founded  as  that  of  a  street  railway  company,  and  in 
the  absence  of  express  legislative  direction  to  the  contrary,  there  is 
to  be  no  yielding  to  any  other.  The  provision  that  the  telephone  and 
telegraph  lines  shall  not  incommodate  the  public  in  the  use  of  the 
street,  in  Section  3,461,  does  not  help  the  defendant.  The  inconven- 
ience must  be  determined  when  the  enjoyment  of  the  franchise  is 
entered  upon. 

After  rights  have  been  acquired  by  the  outlay  of  capital  and  user, 
there  must  be  express  legislative  sanction,  at  least,  to  warrant  a 
court  in  finding  a  use  of  the  street  to  be  an  interference  with  public 
travel  which  was  not  so  when  it  began.  It  should  be  noted  in  this 
connection,  too,  that  the  plaintiff  performs  a  very  important  quasi 
public  duty,  and  is  in  fact  a  common  carrier  of  messages.  It  is  given 
the  power  of  condemnation  on  that  ground  alone.  Pierce  z1.  Drew,  136 
Mass.,  75;  Hackett  r.  State,  105  Ind.,  250. 

Coming  now  to  apply  the  principle  just  under  discussion  to  the  case 
at  bar,  what  do  we  find  ?  For  ten  years  the  plaintiff  has  exercised  the 
franchise  of  occupying  the  streets  along  defendant's  lines  with  its 
poles  and  wires,  conducting  a  telephone  business  with  a  single  wire 
circuit  and  an  earth  return.  This  mode  of  return  was  universally 
employed  when  it  began,  and  is  to-day  in  general  use.  It  has  con- 
structed a  valuable  plant,  many  parts  of  which  will  have  to  be  changed 
at  great  expense  if  it  is  to  adopt  the  only  system  which  will  obviate 
the  difficulty  it  now  encounters  from  the  operation  of  defendant's  rail- 
way. I  refer  to  the  metallic  circuit.  It  is  admitted  by  every  one  that 
if  the  telephone  company  were  to  make  every  one  of  its  lines  a  com- 
plete metallic  circuit,  with  the  return  wire  parallel  with  the  outgoing 
wire,  the  disturbance  both  from  induction  and  earth  leakage  would 
be  completely  removed.  It  is  obvious  that  if  the  circuit  never  came 
into  contact  with  the  earth,  the  electricity  dumped  into  the  ground  by 
defendant  could  not  reach  the  telephone  wire,  and  so  no  disturbance 
could  arise  there.  And  it  is  also  a  well-ascertained  fact  that  if  the 
two  wires  of  the  circuit,  the  outgoing  and  the  return,  are  parallel  an<- 
the  same  length,  no  effect  will  be  perceptible  from  induction  by  r, 
third  parallel  wire  of  another  circuit,  however  variable  may  be  the 
current  on  that  wire.  This  is  because  the  induction  which  actually 
takes  place  upon  each  of  the  wires  of  the  circuit  results  in  currents 
of  equal  intensity  and  variability  in  opposite  directions,  which  being 
on  the  same  circuit  exactly  neutralize  each  other. 


APPENDIX   A.  365 

To  construct  such  a  circuit  for  every  subscriber  would  entail  an 
expense  upon  plaintiffs,  perhaps,  even  greater  than  the  original  out- 
lay. Nor  does  it  seem  practicable  to  have  metallic  circuits  in  disturbed 
districts  and  allow  the  other  lines  to  remain  grounded,  because  of  the 
difficulty  in  arranging  the  switchboards  at  the  exchange  by  which  sub- 
scribers are  connected  with  each  other,  and  for  the  further  reason  that 
in  order  to  connect  a  metallic  circuit  with  a  grounded  circuit,  the  re- 
turn wire  of  the  metallic  circuit  must  be  grounded  at  the  exchanges. 
The  result  is  that  the  circuit  then  made  between  the  two  subscribers 
is  a  grounded  circuit  with  a  long  leg  and  a  short  leg  of  wire  parallel 
in  the  disturbed  district.  The  difference  in  the  length  of  the  two 
wires  prevents  the  neutralizing  effect  of  the  induced  current  in  one 
wire  upon  the  opposite  induced  current  in  the  other,  because,  by 
reason  of  the  different  lengths,  that  part  of  the  induced  currents  said 
to  be  produced  by  static  induction  is  unequal.  Moreover,  to  put  up 
metallic  circuits  through  the  disturbed  districts  and  to  make  the 
necessary  alterations  in  the  switchboard  would  entail  an  expense,  not 
nearly  so  heavy,  of  course,  as  a  complete  conversion  into  a  metallic 
circuit,  but  which  would  be  quite  substantial.  There  remains  to  con- 
sider what  is  called  the  McCluer  device,  which  consists  in  a  large  wire 
carried  into  the  disturbed  district  with  which  are  connected  all  the 
return  wires  of  the  telephones.  This  main  is  grounded  at  a  point 
away  from  danger  of  earth  leakage.  It  is  likely  that  such  a  device 
would  get  rid  of  earth  leakage,  but  it  would  have  no  practical  preven- 
tive effect  upon  the  disturbances  by  induction,  which,  as  I  have  said, 
make  up  about  half  of  the  troubles.  The  expense  of  such  a  device 
would  not  be  large,  still  it  would  be  something.  It  follows,  from 
what  has  been  said,  that  if  the  defendant  is  permitted  to  use  its  pres- 
ent single-trolley  system,  it  will  require  the  plaintiff  either  to  lose  the 
business  of  many  subscribers,  or  it  will  have  to  go  to  an  enormous 
expense  to  obviate  all  difficulty  or  to  a  less  expense  to  get  partial 
relief. 

The  plaintiff  invested  large  capital  on  the  faith  of  its  present  mode 
of  enjoyment  of  its  franchise.  It  has  continued  in  such  enjoyment 
for  some  ten  years.  To  change  involves  loss  and  expense.  Clearly, 
then,  it  cannot  be  deprived  of  what  so  nearly  approximates  a  vested 
right  without  clear  legislative  intent. 

Is  it  impossible,  then,  for  the  defendant  to  run  an  electric  railway 
along  its  streets  without  making  these  disturbances?  It  is  practically 
conceded,  although  there  was  some  slight  evidence  to  the  contrary, 
that  if  instead  of  a  single  trolley  wire  and  an  earth  return  two  trolley 
wires  were  used,  one  for  the  positive  and  the  other  the  negative  cur- 
rent, the  difficulties  would  be  just  as  completely  obviated  as  if  the 
telephone  company  used  a  metallic  circuit.  There  is  such  a  system 
in  use  in  a  number  of  cities  of  the  country.  There  are  two  in  opera- 
tion in  this  city  and  two  or  three  more  are  projected  here.  In  such  a 


366  THE   ELECTRIC    RAILWAY. 

system  the  electricity  is  carried  from  one  wire  down  through  one  trolley 
wheel  and  mast  to  the  motor  of  the  moving  car,  and  returns  from  the 
motor  to  the  other  wire  by  means  of  a  second  trolley  wheel  and  mast. 
It  is  said  it  is  wholly  impracticable. 

The  single-trolley  system  is  in  use  on  nine-tenths  of  the  electric  rail- 
way systems  in  the  United  States.  This  arises  doubtless  from  two 
facts :  First,  that  it  is  perhaps  one-fourth  cheaper  in  its  outside  con- 
struction; and,  second,  because  in  single-track  railways,  of  which 
there  are  many  more  than  double  track,  where  it  is  necessary  to  have 
many  switches  and  turn-outs,  the  complications  of  wires  overhead 
increase  much  more  rapidly  with  a  double  trolley  than  a  single  trolley. 
But  in  the  case  at  bar  we  have  a  double  track  from  one  end  of  the 
road  to  the  other,  so  that  no  switches  are  required.  Mr.  Short,  who  is 
a  skilled  mechanician  engaged  in  a  company  which  bears  his  name 
and  which  erects  both  the  single  and  the  double  trolley  systems,  says 
that  he  recommends  the  single  trolley  for  single  tracks  and  the  double 
trolley  for  double  tracks.  He  seems  the  only  witness  on  either  side 
that  is  free  from  suspicion  of  bias. 

It  is  admitted  by  many  of  defendant's  witnesses  that  electrically 
the  double-trolley  system  is  exactly  as  good  as  the  single-trolley,  and 
this  must  be  so,  because  a  return  by  wire  makes  quite  "as  good  a  cur- 
rent as  by  the  earth.  The  claim  that  electricity  in  the  wheels  passing 
to  the  track  gives  additional  traction  is  conjectural,  and  is  not  ap- 
parent in  a  practical  comparison  of  the  grades  ascended  by  the  cars  on 
the  two  systems.  The  objection  to  the  double-trolley  system  is  the 
mechanical  difficulty  in  making  proper  switches  and  in  supporting 
the  superstructure.  In  the  double-track  road,  like  the  defendant's,  the 
first  difficulty  does  not  arise,  and  the  second  difficulty  has  in  fact  been 
overcome  in  every  double-trolley  system  which  has  been  erected.  On 
the  whole,  then,  it  seems  to  me  that  there  is  no  serious  obstacle  to 
defendant  using  the  double  trolley. 

The  defendant  cannot  rely  on  an  estoppel.  It  was  notified  by  the 
plaintiff  as  early  as  March  12,  1889,  some  three  months  or  more  before 
its  electrical  plant  was  put  into  position,  that  the  use  of  the  single- 
trolley  system  would  interfere  with  and  injure  the  use  of  the  plain- 
tiff's telephone  lines. 

But  it  is  said  that  the  injuries  here  occasioned  are  not  cognizable  in 
the  courts,  even  if  the  telephone  company  is  to  be  regarded  as  a  pri- 
vate property  owner  in  the  enjoyment  of  the  telephone  franchise,  and 
the  case  of  Frazier  v.  Siebern,  16  Ohio  St.,  614,  is  relied  on  in  this 
connection.  That  was  a  case  between  adjoining  proprietors,  where 
the  defendant  dug  a  well  on  his  premises  and  knowingly  diverted  per- 
colating waters  which  made  a  spring  on  the  plaintiff's  premises  and 
dried  the  spring.  This  was  held  to  be  damnum  absque  injuria.  There 
is  no  parallel  between  that  case  and  the  one  before  us.  There  the 
spring  owner  had.  no  ownership  in  the  percolating  waters  until  they 


APPENDIX   A.  367 

appeared  on  his  property,  and  the  injury  he  suffered  arose  simply 
from  his  neighbor  making  his  own  that  to  which,  while  it  was  on  his 
premises,  he  was  lawfully  entitled.  In  the  case  at  bar,  the  disturb- 
ances, in  their  twofold  origin,  present  slightly  different  circumstances, 
but  call  for  the  application  of  the  same  principle.  The  earth  leakage 
arises  from  the  defendant  pouring  electricity  into  the  earth,  which, 
following  a  course  as  natural  for  it  as  the  seeking  of  a  lower  level  is 
for  water,  comes  upon  the  premises  of  plaintiffs  subscribers,  and  by 
getting  upon  the  wires  of  the  telephone  does  harm.  The  plaintiff,  by 
contract  with  its  subscribers,  has  a  right  to  have  its  wire  where  it  is, 
and  for  the  purposes  of  this  discussion  has  exactly  the  same  right  to 
object  to  the  presence  of  electricity  on  its  premises  caused  by  defend- 
ant and  resulting  in  damage  as  would  the  subscriber  himself.  It  is 
impossible  to  distinguish  such  an  injury  in  principle  from  the  case  of  one 
discharging  filthy  water  into  the  ground  so  that  it  shall  percolate  into 
another's  premises  and  there  do  damage,  or  of  one  causing  smoke 
and  cinders  to  be  constantly  thrown  into  one's  windows  and  injuring 
one's  enjoyment  of  one's  property.  These  are  all  examples  of  nui- 
sances which  have  been  held  to  give  a  right  of  redress. 

Ballard  v.  Tomlinson,  29  Ch.  D.,  116;  Ry.  Co.  v.  Gardiner,  45  Ohio 
St.,  309. 

As  was  said  in  Reinhardt  r.  Mestasti,  42  Ch.  D.,  685,  "  the  principle 
governing  the  jurisdiction  of  the  court  in  cases  of  nuisance  does  not 
depend  on  the  question  whether  the  defendant  is  using  his  own,  reason- 
ably or  otherwise.  The  question  is,  Does  he  injure  his  neighbors?" 

The  disturbance  by  induction  is  of  similar  character,  except  that 
the  force  is  applied  from  one  wire  to  the  other  through  the  air  instead 
of  the  earth.  If,  as  we  have  found,  defendant  is  not  entitled  to  inter- 
fere with  plaintiff's  enjoyment  of  the  telephone  franchise,  here  is  a 
direct  act  of  interference. 

Then  it  is  said  no  claim  can  arise  for  disturbances  by  the  defendant, 
because  there  are  similar  disturbances  from  other  causes,  for  which  the 
defendant  is  not  responsible,  and  Woodz>.  Sutcliff,  2  Simons  N.  S. ,  163, 
is  cited  upon  this  point.  That  was  a  case  where  the  injury  sought  to 
be  enjoined  was  the  pollution  of  a  stream  from  which  plaintiff  had,  in 
time  past,  drawn  water  for  his  business.  One  of  the  reasons  given  by 
the  vice-chancellor  for  refusing  the  injunction  was  that  others  than  the 
defendant  were  polluting  the  stream.  The  real  basis  of  the  decision 
was  the  laches  of  the  defendant  in  asserting  his  right,  for  he  had  pro- 
vided a  new  supply  of  water  and  had  not  used  the  river  for  some 
time.  This  case  presented  no  difficulty  in  considering  the  case  at  bar, 
first,  because  there  are  no  substantial  disturbances  shown  other  than 
those  caused  by  defendant,  and,  second,  because  the  case  itself  is  not 
sound  authority.  (See  Crump  v.  Lambert,  3  Eq.  Cas.  ,414;  Crosky  v. 
Lightowler,  2  Ch.,  478;  Walter  v.  Selfe,  4  DeGex  &  S.,  315.)  In  the  last 
case  the  Court  said  that  because  one  man  was  maintaining  a  nui- 


368  THE   ELECTRIC    RAILWAY. 

sance  against  the  plaintiff  was  no  reason  why  defendant  should  set  up 
an  additional  nuisance. 

We  find,  then,  that  defendant  is  inflicting  a  legal  injury  upon  the 
plantiff  in  the  nature  of  a  nuisance  from  which  has  already  arisen 
loss,  and  which  must  inevitably  cause  loss  in  the  future,  constantly 
recurring.  It  is  said  that  the  damage  is  not  irreparable,  because 
the  plaintiff  can  expend  money  and  avoid  it,  and  in  the  same  way 
can  arrive  at  its  exact  loss,  and  that,  therefore,  its  remedy  is  not 
by  injunction,  but  at  law.  Neither  of  these  claims  can  be  sus- 
tained. The  most  frequent  exercise  by  a  court  of  equity  of  the  power 
of  injunction  is  to  prevent  the  continual  recurrence  of  injuries  from 
nuisance.  The  ground  is  that  the  plaintiff  should  not  be  put  to  a 
multiplicity  of  suits  and  endless  litigation.  To 'say  that,  in  order 
to  entitle  a  man  to  obtain  an  injunction  against  such  injury,  he 
should  not  be  able,  by  the  expenditure  of  even  vast  amounts,  to  avoid 
the  injury,  is  to  say  that  no  injunctions  can  ever  issue  for  such  a 
cause.  The  point  is  that  he  is  not  obliged  to  expend  money  to  protect 
himself  when  a  neighbor  injures  him,  but  he  may  appeal  to  the  courts; 
and  when  upon  the  law  side  he  finds  that  the  remedy  there  afforded 
is  inadequate  because  of  the  necessity  for  bringing  a  separate  suit  for 
each  injury,  he  may  fairly  say  that  by  appeals  to  legal  tribunals  he 
cannot  repair  his  damage,  and  therefore  his  loss  will  be  irreparable. 
As  to  the  ascertainment  of  damages,  it  is  by  no  means  true  that  in 
each  suit  the  entire  cost  of  introducing  a  metallic  circuit  or  a  McCluer 
device  would  be  the  measure  of  damages  for  this  sort  of  interference, 
and  the  very  reason  for  going  into  a  court  of  equity  is  to  get  into  a 
forum  where  all  the  injuries  can  be  considered  together. 

The  order  of  the  court  will  therefore  be  that  the  defendant  be  enjoined 
perpetually  from  the  use  of  the  system  of  electric  railway  propulsion 
as  now  operated  by  them,  or  any  other  which  will  occasion  similar 
disturbances  to  those  now  caused  by  defendant's  single-trolley  system. 
The  order  of  injunction  will  not  take  effect  until  six  months  from  this 
day,  with  leave  to  the  defendant  to  apply  to  the  court  hereafter  for 
further  time,  if  necessary,  in  a  bona  fide  effort  to  make  the  necessary 
changes.  The  costs  of  the  action  must  be  paid  by  the  defendant. 
Decree  accordingly. 


APPENDIX   B. 


INSTRUCTIONS  TO  LINEMEN. 


For  the  trolley  wire,  hard  drawn  copper  is  used  to  a  very  great 
extent,  its  size  depending  on  the  service  required.  No.  o  B.  &  S. 
gauge  is  a  very  convenient  size  and  is  generally  used,  although  the 
wire  may  be  smaller  with  sub-feeders  as  explained.  Silicon-bronze 
wire  has  also  been  largely  used  on  account  of  its  great  tensile  strength. 
Copper  is  quite  strong  enough,  however. 

Span  wires  should  be  No.  i  B.  &  S.  gauge,  galvanized,  wiped,  Swedish 
iron  wire  if  the  trolley  wire  to  be  used  is  No.  o.  They  may  be  of 
smaller  size  if  a  smaller  trolley  wire  is  used. 

Pull-offs  and  anchor  guys  should  be  the  same  size  as  the  span  wires. 

For  guard-wire  spans,  use  No.  8  B.  &  S.  gauge,  galvanized,  wiped, 
Swedish  iron  wire. 

For  longitudinal  guard  wires,  use  No.  10  B.  &  S.  gauge,  galvanized, 
wiped,  Swedish  iron  wire. 

In  case  of  extra  heavy  or  long  stretches,  two  or  more  strands  of  the 
above  iron  wire  may  be  twisted  together.  Stranded  wires  of  galvanized 
iron  have  been  used  for  ordinary  lengths,  and  are  preferred  by  some. 

POLE    CLAMPS. 

The  poles  should  be  fitted  with  suitable  pole  clamps,  so  that  the 
wire  may  be  readily  adjusted  to  the  required  weight.     It  is  very  im- 
portant that  the  height  of  the  trolley  wire  from 
the  track  should  be  uniform,  and  by  using  pole 
clamps  this  uniformity  can  easily  be  secured. 
Great  care  should   be    taken    in   this  respect. 
Fig.  127  shows  one  style  of  pole  clamp  which 
may  be  used,  and  Figs.  128-132  several  insula- 
tor holders  for  substantially  the  same  purpose. 
There  should  be  two  clamps  on  each  pole,  one      FJG  I27~IJoLE~ CLAMP. 
for  trolley  spans,  the   other   for  guard  spans. 

In  certain  cases  where  a  number  of  crowfoot  wires  diverge  from 
one  pole  it  may  be  found  necessary  to  make  use  of  more  than  two 
clamps  on  the  pole.  The  clamp  to  which  the  guard  span  is  to  be 
attached  may  be  smaller  and  lighter  than  that  intended  for  the 
trolley  span. 

24  369 


370  THE    ELECTRIC    RAILWAY. 

After  the  wires  have  been  erected  and  lined  up  they  should  be  more 
closely  adjusted  by  loosening  or  tightening  the  bolts  in  the  clamps 
which  hold  the  spans. 

In  some  cases  where  the  spans  are  extremely  long  or  heavy  it  may 


FIGS.  128-132.— INSULATED  HOLDERS 

be  advisable  to  use  a  third  span  fastened  to  clamps  and  allowed  to 
sag  toward  the  trolley  span,  which  should  be  secured  to  it  for  addi- 
tional support. 

SPANS. 

In  the  erection  of  a  line  the  trolley  spans  should  be  the  first  wires 
stretched,  and  should  be  pulled  up  into  their  permanent  position.  Or- 
dinarily, they  should  be  as  tight  as  two  men  can  pull  them  with  the 
help  of  a  single  3-inch  block  and  fall.  The  tension  should  be  from 
300  to  600  pounds.  The  guard  spans  should  be  as  nearly  perfectly 
insulated  as  possible  from  the  trolley  spans  and  the  poles.  This  is 
accomplished  by  stretching  them  from  pole  clamps  to  which  nothing 
is  attached  but  the  guard  spans.  Anchor  guys  should  be  attached  to 
the  trolley-span  pole  clamps  and  not  to  the  guard-span  clamps. 

Next,  guard  spans  should  be  stretched,  and  should  ordinarily  be 
pulled  tight  with  the  vise  and  strap,  and  should  have  about  100  pounds 
tension  on  them.  In  extra  long  and  heavy  stretches  more  tension 
should  be  placed  upon  both  trolley  and  guard  spans  than  that  above 
mentioned,  but  care  shoiild  be  taken  that  the  spans  in  every  case  shall 
be  as  loose  as  steadiness  and  appearance  will  allow,  since  the  more 
tension  there  is  on  them  the  greater  liability  is  there  of  breakage. 
The  attachment  of  the  wires  to  the  eyebolt  of  the  clamps  should  be 
made  by  a  long  and  close  half-connection. 


APPENDIX    B. 


371 


EAR   BODIES,  OR    SPAN-WIRE   CLAMPS. 

After  the  spans  are  up  the  next  work  is  to  locate  and  put  on  the  ear 
todies.  On  straight  line  work  the  ear  bodies,  if  similar  to  the  ones 
shown  in  Figs.  133-146,  are  "  sprung  on  "  the  wire.  Figs.  147-149  show 
several  of  the  many  kinds  of  ear  bodies  that  may  be  used  on  curve 


FIGS.  133-137.— SPAN-WIRE  CLAMPS. 

work.  These  should  be  "  cut  into"  the  span,  that  is,  the  proper  point 
on  the  span  wire  having  been  determined  by  means  of  a  plumb  line, 
the  wire  is  cut  at  this  point  and  the  ear  inserted,  as  shown  in  Fig.  150. 
Sometimes  insulating  holders,  such  as  shown  in  Figs.  151-153.  ar® 
used  in  this  work. 


372 


THE    ELECTRIC    RAILWAY. 


Figs.  154-157  show  some  of  the  types  of  "  pull-offs,"  which  are  also 
intended  for  curve  work,  and  Figs.  H7-H9  several  bracket  clamps 
used  in  special  cases. 

"  RUNNING"  TROLLEY  WIRE. 

Next,  the  trolley  wire  should  be  anchored  securely  at  one  end  of  the 
line  and  reeled  out  for  a  distance  of  1,000  feet,  or  as  far  as  is  found 
convenient;  temporary  slings  of  iron  wire  should  be  placed  over  the 


FIGS.  138-146.— SPAN-WIRE  CLAMPS. 

span  wires  and  the  trolley  wire  raised  up  on  a  tower  wagon  and  hung 
in  these  slings. 

Hauling  clamps  should  be  placed  on  the  trolley  wire  and  a  tempo- 
rary anchor  made,  the  wire  being  pulled  up  tight  by  four  or  five  men 
with  double  "block  and  tackle."  The  permanent  anchor  should  then 
be  pulled  up  tight  and  fastened  to  a  pole  so  as  to  securely  hold  the 
tension  placed  upon  the  trolley  wire. 

On  reaching  a  curve  the  wire  should  be  pulled  up  tight  to  this  point, 


APPENDIX    B. 


373 


anchored,  and  then  run  around  the  curve,  allowing  as  much  slack  as 
may  be  needed  to  make  the  curve.  On  the  curves  the  slings  should 
be  attached  to  the  span  wires  or  pull-offs  in  such  a  way  that  they  can- 
not slip  along  them.  The  trolley  wires  should  be  placed  a  little  inside 


FIGS.  147-149.— CLAMPS  FOR  CURVE  WORK. 


FIG.  150.— "CUTTING  IN  '  A  SPAN-WIRE  CLAMP 


FIGS.  151-153.— INSULATOR  HOLDERS 

of  their  usual  position,  as  judgment  may  dictate,  and  pulled  compara- 
tively tight.  The  wire  should  then  be  anchored  both  ways  at  the  end 
of  the  curve,  so  as  to  make  a  fixed  point. 


374  THE    ELECTRIC    RAILWAY. 

The  construction  may  be  continued  in  the  same  manner  as  before 
from  this  point  on. 

After  running  and  hanging  up  the  trolley  wire  the  ears  or  clamps 
should  be  put  on. 

"  EARS"  OR  INSULATOR    CLAMPS. 

The  same  clamps  should  be  used  on  curves  as  on  straight  lines, 
excepting  when  anchors  or  splices  are  introduced.  Some  ears  or  clamps 
have  sides  or  points,  which,  being  bent  over  the  wire,  clamp  them 
to  it.  (See  Figs.  133-146  with  paragraph  on  "  ear  bodies"  for  "  ears.") 
If  clamps  are  used  which  require  soldering  they  should  be  fitted  to 
the  wire  upside  down,  closely  pressed  around  with  great  care,  so  as  not 
to  cut  or  damage  the  trolley  wire,  and  then  carefully  soldered  with 
the  ordinary  lineman's  soldering  iron  for  railway  work.  All  the 
clamps  should  be  soldered  on  and  the  line  then  turned  over  so  that  the 
clamps  will  be  in  their  proper  position.  It  is  not  possible  to  solder 
on  one  clamp,  turn  it  upright,  and  then  go  on  to  the  next,  and  at  the 
same  time  have  a  straight,  untwisted  line.  In  repairing  a  line  on 


FIGS.  154-157.— "  PULL-OVER  "  BRACKETS. 

which  soldered  insulator  clamps  are  used  it  is  necessary  to  do  one  of 
two  things :  First,  to  give  the  wire  a  half  twist,  then  solder  on  the 
clamp  in  a  reversed  position,  and  when  the  soldering  is  done  allow  the 
wire  to  spring  back  into  its  original  position,  thus  turning  the  clamp 
into  its  proper  place ;  or,  second,  to  solder  the  clamp  on  when  in  its 
proper  position,  which  is  an  exceedingly  difficult  thing  to  do. 

The  clamps  used  for  splicing  should  fit  any  of  the  insulators  in  use 
on  the  line.  The  method  of  using  splicing  clamps  is  explained  in 
another  place. 

The  strain  clamps  for  anchoring  should  fit  any  of  the  insulators  or 
ear  bodies  in  use  on  the  line.  They  should  be  similar  to  the  ordinary 
clamps  so  far  as  the  groove  for  holding  wire  is  concerned,  and  should 
be  put  on  in  the  same  way. 

GUARD-SPAN     HANGERS. 

In  the  same  way  that  insulators  are  used  the  guard-wire  hangers 
should  be  employed,  several  styles  of  hanger  being  shown  in  Figs. 


APPENDIX    B. 


375 


158-160.     For  straight  line  work  the  straight  line  guard  hanger  should 
be  "  sprung  on"  the  wire  with  the  insulator  down. 

The  longitudinal  guard  should  be  suspended  from  below,  not  over 
the  insulator,  by  means  of  the  common  insulator  tie  of  No.  1 2  wire. 


FIGS.  158-160. 

On  curves  single  and  double  guard-wire  curve  suspensions  should 
be  employed,  the  longitudinal  guard  wire  being  secured  to  the  insula- 
tor by  a  stout  tie. 

ANCHORS. 

Double  anchors  should  be  put  in  every  few  hundred  (500  to  1,000) 
feet  on  straight  line  work,  and  should  be  put  in  at  each  end  of  every 


curve.  By  double  anchors  are  meant  anchors  which  hold  the  line  both 
ways.  Figs.  161-162  show  how  these  anchors  should  be  installed. 

A  single  anchor  must  never  be  put  in  except  at  the  end  of  a  line. 
Anchoring  is  half  the  line  construction,  and  if  not  well  done  will  cause 
endless  trouble. 

The  following  instructions  for  anchoring  should  be  carefully  noted  : 

For  the  immediate  connection  to  the  trolley  wire,  use  a  short  strain 
clamp. 

The  same  wire  that  is  used  for  spans  should  be  used  for  anchors, 


and  should  be  pulled  about  one-half  as  tight.     Some  insulator  should 
be  put  into  each  anchor  wire  about  2  feet  from  the  anchor  clamp. 
For  double-track  construction  of  anchors,  see  Fig.  162  above. 


376 


THE    ELECTRIC    RAILWAY. 


When  the  trolley  wire  requires  splicing  a  "  splicing  ear"  should  be 
used  in  connection  with  an  insulator.  If  a  splicing  ear  like  the  one 
shown  in  Fig.  163  is  used,  the  end  of  the  wire  after  being  passed  up 


FIG.  163.— SPLICING  "EAR." 

through  the  proper  holes  and  soldered  should  be  turned  back  over 
the  top,  as  shown  in  the  figure,  and  not  left  sticking  up  straight. 

FEEDERS. 

In  "  cutting  in  "  feeders,  measurements  should  be  made  of  the  width 
of  street,  distance  between  trolley  wires,  etc.,  and  the  feeder  span 
made  up  in  the  shop  ready  to  install,  since  trouble  will  be  found  in 
making  up  a  span  on  the  street.  All  feeder  spans  should  be  put  up  as 
represented  in  Fig.  164. 

The  wire  used  for  connecting  the  feeder  with  the  clamp  or  ear 
should  be  of  the  same  size  and  material  as  the  trolley  wire.  The  wire 
on  the  dead  end  of  the  feeder  span  should  be  the  same  size  and  kind 
as  used  for  span  wires.  The  insulator  on  the  dead  end  should  be  close 
to  the  ear  and  not  next  to  the  pole. 

The  insulator  at  the  other  (live)  end  should  be  close  to  the  pole, 
and  the  side  feed- fastened  to  the  insulator  by  a  half  connection.  The 


FIG.  164.— ARRANGEMENT  OF  FEEDER. 
insulator  should  then  be  attached  to  the  pole  clamp  by  the  regular 
wire  used  for  spans,  allowing  about  two  feet  between  the  pole  cap 
and  the  insulator.  Side  feeds  should  not  be  put  in  on  curves. 

INSULATING    JOINTS. 

It  is  sometimes  necessary  to  divide  the  trolley  wire  into  sections 
insulated  from  each  other.  This  is  done  by  the  insertion  of  "  insulat- 
ing joints." 

Insulating  joints  should  be  inserted  at  spans,  in  the  same  manner 
as  a  splicing  ear. 


APPENDIX   B. 


377 


If  such  an  insulating  joint  as  the  one  shown  in  Fig.  165  is  used,  the 
span  wire  should  be  attached  to  its  central  segment. 

Connection  can  be  made  with  a  feeder  by  the  ordinary  side  feed 


FIG.  165.— INSULATING  JOINT. 

simply  by  clamping  the  side  feed  wire  into  the  tongue  of  the  insulat- 
ing joint,  by  means  of  a  screw  provided  for  this  purpose. 

It  is  sometimes  advisable  in  the  construction  of  overhead  lines  to 
run  a  wire  from  each  side  of  an  insulating  joint  to  a  switch  on  the 
pole,  so  that  the  insulating  joint  may  be  short-circuited  in  case  it  is 
desirable  to  throw  the  two  sections  of  line 
together.  One  method  of  doing  this  is 
shown  in  Fig.  166. 

The  kind  ot  insulating  joint  shown  in  Fig. 
165  may  be  used  as  a  lightning  arrester,  if 
supplemented  by  a  special  device  having  a 
series  of  small  breaks  of  about  one-sixteenth 
of  an  inch  each,  which  should  be  "  cut  into  " 
the  span  wire  attached  to  the  ear  and  dead 
grounded  at  the  other  end  on  the  pole,  as- 
suming that  iron  poles  are  used.  If  wooden 
poles  are  used  this  ground  should  be  made 
by  leading  a  wire  down  the  pole  and  fasten- 
ing it  to  the  rails. 


LOCATION    OF    TROLLEY    WIRE. 

The  trolley  wire  should  be  located  as  fol- 
lows : 

On  straight  line  work  the  wire  should  be 
over  the  center  of  the  track. 

At  curves  the  wire  should  be  placed  on 
the  inside  of  the  curve,  its  distance  from  the 
center  of  the  track  depending  on  the  degree 
of  curvature. 


\ 


FIG.  166.— SWITCH  AROUND  IN- 
SULATING JOINT. 


Where  lines  branch  from  each  other  frogs 
are  used  for  directing  the  trolley  wheels  to 
the  proper  line.  When  the  line  branches  off  to  the  right  use  a  right- 
hand  frog,  and  when  to  the  left,  a  left-hand  frog,  and  when  the  track 
splits  symmetrically  a  symmetrical  frog  should  be  used. 

In  case  the  angle  between  the  diverging  tongues  is  not  the  same  as 


378 


THE   ELECTRIC    RAILWAY. 


that  which  the  trolley  wires  make,  the  tongues  should  be  slightly  bent 
to  make  the  two  angles  the  same.  Some  frogs  are  made  with  lugs  on 
the  sides  for  the  attachment  of  an  insulating  truss,  so  that  guy  wires 
may  be  fastened  thereon  to  steady  the  frog  and  prevent  i-ts  tilting. 


FIG.  107.  -PLACING  FROGS. 

Frogs  should  not  be  secured  to  the  trolley  wire  until  the  proper  loca- 
tion is  assured.  With  the  line  at  its  usual  height,  18'  6"  to  19'  6",  the 
proper  place  may  be  found  as  follows : 

In  Fig.  167  let  R  X  Z  Y  S  represent  the  position  of  the  track. 

Let  o  represent  the  center  of  the  triangle,  X  Y  Z;  that  is,  the 
point  of  intersection  of  right  lines  bisecting  the  three  angles  X,  Y,  Z. 
The  position  of  the  frog  should  be  directly  over  the  spot  (o).  Observe 


FIGS.  168-175.— FROGS. 

that  this  throws  the  main  line  a  few  inches  out  of  center,  and  like- 
wise the  branch  line  a  little  out  of  center.  This  is  all  right,  however, 
and  is  the  secret  of  making  the  frog  work  successfully.  Figs.  168-175 
show  a  few  types  of  frogs. 


APPENDIX    B. 


379 


DIAGONAL   AND    RIGHT-ANGLE   CROSSINGS. 

Where  trolley  wires  cross  there  should  be  used :  First,  a  diagonal 
crossing,  if  the  lines  make  an  acute  angle  of  less  than  60  degrees; 
second,  a  right-angle  crossing,  if  the  acute  angle  is  between  60  and 


FIGS.  176-179.— TROLLEY-WIRE  CROSSING. 

90  degrees.     The  method  of  putting  up  diagonal  and  right-angle  cross- 
ings is  the  same  as  that  for  frogs.     See  Figs.  176-179. 

GUARD    WIRES. 

Guard  wires  should  be  insulated  from  everything  else.  They  should 
be  cut  into  sections  at  the  same  points  as  the  trolley  wire,  and  at  every 
i, ooo  feet  besides.  The  guard  wires  should  be  directly  over  the  trolley 
wires,  that  is,  one  guard  wire  to  each  trolley  wire. 

Before  the  line  is  left  as  completed  all  insulators,  pole  clamps,  and 
other  parts  of  the  line  material  needing  it  should  be  painted  neatly 
and  with  care,  that  the  parts  may  be  kept  from  rusting. 


POLE     SPECIFICATIONS. 

If  wooden  poles  are  used  they  are  generally  of  cedar,  chestnut,  or 
Georgia  pine,  the  latter  being  usually  squared  and  pointed  at  the 
top.  Round  poles  should  be  trimmed,  smoothed  and  pointed,  and  the 
butts  of  all  wooden  poles  should  be  painted  with  some  preserving 
compound.  The  length  should  be  not  less  than  28  feet,  with  mean 
diameters  of  at  least  7  and  9  inches  at  the  top  and  bottom  respectively. 

Iron  poles  should  be  at  least  28  feet  long,  and  if  made  in  sections,  as 
the  Walworth  pole,  the  respective  diameters  of  the  sections  should  be 
generally  6,  5,  and  4  inches.  There  are  many  pole  manufacturers,  but 
the  Walworth  Co.  is  perhaps  most  widely  known.  Iron  poles  should 
have  insulated  caps  and  cast-iron  trimmings,  though  these  latter  are  not 
absolutely  necessary.  All  poles  should  be  set  six  feet  in  the  ground, 


380  THE    ELECTRIC    RAILWAY. 

with  tops  on  a  level,  about  20  feet  above  the  level  of  the  rails.  For  iron 
poles,  the  rake  should  be  about  five-sixteenths  of  an  inch  to  one  foot  of 
length,  and  for  wooden  poles  at  least  twice  as  much,  this  depending  of 
course  upon  circumstances.  The  object  aimed  at  is  that  when  the  strain 
of  the  span  and  the  other  wires  is  upon  the  poles  they  shall  stand 
straight.  All  poles  should  be  well  grouted  with  broken  stone  and  ce- 
ment, and  it  is  well  to  place  a  large  stone  at  the  heel  of  the  pole,  also 
one  in  front  of  the  pole  just  below  the  surface  of  the  earth,  so  that  the 
pole  shall  be  well  braced.  The  distance  apart  of  the  poles  will  depend 
upon  circumstances;  usually  about  125  feet  apart  will  answer.  All 
poles  should  be  painted  once  before  being  set,  and  again  afterward, 
so  that  they  may  present  a  good  appearance. 


APPENDIX  C. 


ENGINEER'S   LOG-BOOK. 


January  17,    1892. 
COAL  USED,  5,650  LBS.  WATER  USED,  36,360  LBS. 

CONDITION  OF  TRACK. 

Muddy. 


CARS  IN  USE. 
Standard,          8. 
Double  truck,  i. 
Trailers,  2. 

NOTE   TIME   AND    NUMBER   OF 
EXTRA   CARS    IN    LOG. 

Started,          5.50. 
Shut  down,  11.20. 


MACHINES  IN  USE. 
Engines,  A. 
Boilers,  /  and  2. 
Dynamos,  /,  2,  3. 

NOTE   ANY    MACHINES    THROWN 
INTO   USE    IN    LOG. 


TIME. 

INDICATOR 

CARDS. 

AMPERES 

ON   LINE. 

VOLTS  ON 

LINE. 

WEATHER. 

SPECIAL  REPORTS. 

H48.2 

8.00 

C  47-9 

112 

550 

Cold 
clouds. 

0.17 

182 

505 

Heavy    current 
for    about 

six     minutes. 

Dy  n  a  mo   I 
sparked  bad- 

ly .     Cut  it 

out      ana 

12.50 

Snow. 

threiv  in  No. 

1.32 

125 

540 

4- 

2.40 

117 

546 

2-45 

H3 

548 

4-50 

Snow 

ceased. 

6.10 

95 

550 

10.00 

80 

550 

Clear. 

381 


APPENDIX  D. 


CLASSIFICATION   OF   EXPENDITURES   OF    ELECTRIC 
STREET   RAILWAYS. 

COMPILED    BY    H.     I.     BETTIS. 
(£y  permission  ) 

An  authority  upon  railway  accounts  has  said  that "  the  most  remark- 
able diversity  exists  among  railway  companies  in  reference  to  the 
classification  of  their  operating  expenses." 

Undoubtedly  the  statement  was  correct  as  applied  to  steam  railroad 
accounts,  but  could  the  same  writer  have  had  his  experience  in  street 
railway  management  he  probably  would  have  declared  that  there  is 
no  similarity  whatever  in  their  treatment  of  disbursements. 

The  electric  street  railways  of  to-day  are  in  their  infancy,  and  we 
have  but  a  limited  knowledge  of  the  practical  .utility  of  the  various 
parts  and  the  manner  in  which  they  are  operated,  but  with  careful 
attention  to  the  accounts  the  benefits  derived  from  the  various  com- 
binations and  methods  are  readily  seen. 

Also  comparative  statements  can  be  made  from  month  to  month,  by 
which  it  can  be  seen  at  a  glance  wherein  we  have  not  paid  the  proper 
attention  to  certain  parts  of  our  system,  and  demonstrate  that  our  neg- 
lect results  in  dollars  and  cents  on  the  wrong  side  of  the  income 
account. 

At  the  time  of  the  Buffalo  Convention  our  managers  and  superin- 
tendents made  statements  concerning  their  operating  expenses  which 
actually  staggered  one  another.  One  would  state  that  on  his  line 
operation  cost  so  much  per  mile ;  another  would  state  that  it  cost  his 
company  a  much  different  sum  per  mile. 

The  first  had  included,  perhaps,  the  repairs  of  cars  with  wages  of 
motor-men  and  conductors,  while  the  second  might  have  omitted 
repairs  of  cars  and  included  the  cost  of  operating  the  power  house, 
with  or  without  the  cost  of  repairs  on  the  dynamos. 

There  was,  and  is  now,  no  way  in  which  a  comparison  can  be  made 
between  the  costs  of  operating  our  various  street  railways,  and  it  is 
with  this  object  in  view  that  this  manual  has  been  compiled,  hoping 
that  although  it  might  not  suit  all,  it  might  at  least  be  a  guide  to  those 
who  have  not  yet  decided  upon  any  classification,  and  for  those  who 
are  at  all  desirous  of  having  a  standard  or  universal  system. 

Such  a  classification  should  be  as  simple  as  possible,  and  yet  with 
382 


APPENDIX    D.  383 

sufficient  detail  to  afford  the  management  and  owners  an  easy  means 
for  determining  in  what  manner  the  business  of  the  road  could  be  con- 
ducted with  better  success,  where  the  failures  had  been,  and  what  had 
been  the  causes. 

The  classifications  as  given  here  are  not  subdivided  to  the  extent  that 
some  might  think  desirable,  but  sufficiently,  I  think,  for  any  practical 
purposes,  as  any  further  division  would  be  purely  statistical. 

It  has  been  the  author's  intention  to  follow  the  idea  of  the  Interstate 
Commerce  Commission  when  designing  the  standard  classification  for 
steam  roads,  to  separate  the  expenses  which  add  to  the  present  or 
future  value  of  the  property  from  those  which  do  not,  as  the  reader 
will  see  by  comparing  the  general  expenses  and  transportation  ex- 
penses with  the  maintenance  of  way  and  buildings  and  maintenance 
of  equipment,  the  latter  accounts  adding  materially  to  the  value  of  the 
property. 

There  is  a  short  classification  of  construction  expenses  added,  but 
too  much  care  cannot  be  exercised  in  charges  to  these  accounts,  bear- 
ing in  mind,  however,  that  nothing  should  be  charged  to  construction 
and  equipment  except  that  which  adds  to  the  first  or  original  cost  of 
the  property. 

I  wish  to  express  my  thanks  to  Mr.  W.  E.  Baker,  Superintendent  of 
the  West  End  Street  Railway  contract  for  the  Thomson-Houston 
Company,  Boston,  whose  generosity  has  enabled  me  to  profit  by  his 
experience  and  advice  upon  the  subject  treated. 


OPERATING    EXPENSES. 
GENERAL  EXPENSES. 

1.  SALARIES  OF  GENERAL  OFFICERS. — In  this  account  are  included 
the  salaries  of  the  general  officers;  the  heads  of  departments  connected 
with  the  supervision  and  management  of  the  general  business  of  the 
road.     Salaries  of  division  superintendents  and  assistants  may  also  be 
charged  to  this  account.     By  general  officers  are  meant   officers  in 
charge  of  departments  and  whose  jurisdiction  extends  over  the  entire 
road. 

2.  SALARIES  OF  CLERKS  IN  GENERAL  OFFICES. — This   account    em- 
braces the  salaries  of  all  clerks  in  the  general  offices,  clerks  for  heads 
of  departments,  and  all  clerks  not  hereinafter  mentioned. 

3.  MISCELLANEOUS   EXPENSE   GENERAL  OFFICES. —  The   expense   of 
heating,  lighting  the  general  offices;  wages  of  porters,  messengers, 
etc. ;  telephone  service,  and  all  miscellaneous  supplies  and  expenses  of 
the  general  offices  are  charged  to  this  account. 

4.  STATIONERY  AND  PRINTING. — Includes  the  cost  of  all  stationery, 
books,  paper,  stamps,  pens,  pencils,  etc.  ;  also  cost  of  all  printing  of 
blanks,  circulars,  statements,  tickets,  etc.,  and  the  cost  of  advertising. 


384  THE    ELECTRIC    RAILWAY. 

5.  INSURANCE. — Includes  cost  of  insurance  on  property  of  the  com- 
pany, and  against  injuries  to  employees,  and  all  expense  of  collection. 

6.  LEGAL  EXPENSE. — In  this  account  are  included  the  salaries,  fees 
and  expenses  of  attorneys,  witnesses'  fees  and  other  court  expenses. 

7.  INJURIES  AND  DAMAGES. — Expenses  on  account  of  persons  injured 
and  property  damaged,  with 'payments  of  claims,  are  all  chargeable  to 
this  account.     Wages  of  persons  while  disabled,  medical  attendance, 
and  funeral  expenses;  also  wages  of  claim  agent  and  others  connected 
with  the  claim  department.     Lawyers'  fees  and  other  court  expenses 
are  not  chargeable  to  this  account;  nor   are   damages  to   property  be- 
longing to  the  company. 

8.  CONTINGENT  EXPENSES.— This  account  includes  the  miscellaneous 
expenses  not  otherwise  provided   for;  traveling  and  other  expenses 
of  general  officers  and  assistants,  etc.,  etc. 

TRANSPORTATION    EXPENSES. 

1.  CAR  SERVICE. — This  account  includes  the  wages  of  conductors, 
motor-men,  starters,  aids,  inspectors,  and  switchmen ;  cost  of  punches, 
ticket  registers,  sign  sticks,  switch  sticks,  and  miscellaneous  supplies 
for  car  service.     The  wages  of  the  superintendent  of  time-tables  and 
chief  of  conductors,  with  such  clerks  as  may  be  under  them,  should 
also  be  charged  to  this  account. 

2.  CAR-HOUSE  EXPENSE. — This  account  includes  the  wages  of  shed 
foremen,  shifters,  cleaners,  oilers,   wipers,   laborers,    inspectors   and 
watchmen,  except  such  as  are  employed  on  repairs  of  cars.     The  cost 
of  fuel  and  lighting  the  car  houses  and  sheds,  lanterns  and  oil  for 
watchmen,  and  tools  used  by  workmen  on  cars  (cleaning  and  oiling, 
other  work  except  repair)  are  chargeable  to  this  account. 

3.  LUBRICANTS   AND   WASTE  FOR  CARS.— Oil,    grease,    tallow  and 
other  lubricants,  with  waste  used  upon  car  journals  and  motors,  are 
included  in  this  account. 

4.  ELECTRIC  SUPPLIES.— This  account  includes  such  supplies  as  are 
•constantly  needed  for  the  operation  of  the  electric  cars,  but  cannot  be 
charged   to   repairs,   such   as   lamps,    fuses,    carbon   brushes,    trolley 
cord,  etc. 

5.  WRECKING.— Wages  of  those  employed  in  getting  derailed  cars 
on  the  track  and  removing  obstructions  and  wrecks;  tools  used  and 
all  other  expenses  incurred  on  the  same  account.     Expense  of  getting 
cars  back  to  the  car   house  when   broken  down  on  the  line  is  also 
chargeable  to  this  account. 

6.  OPERATION  OF  POWER  HOUSES.— This  account  includes  wages  of 
engineers,  firemen,  coal  shovelers,   dynamo-men,  oilers,  cleaners  and 
others  employed  in  the  power  houses,  except  when  employed  upon 
repairs.     Also  the  cost  of  water,   water   rates,    or   cost   of   pumping 
where  the  company  furnishes  its  own  water-works;  carbon  brushes, 


APPENDIX    D.  385 

fuses,  lamps  and  other  supplies  necessary  for  the  daily  operation  of 
the  power  houses,  and  not  otherwise  provided  for ;  cost  of  heating  and 
lighting  power  houses.  Repairs  and  renewals  of  engines,  boilers, 
dynamos,  switchboards  and  station  fixtures  are  not  chargeable  to  this 
account.  Fuel  and  lubricants  are  also  chargeable  to  separate  accounts. 

7.  FUEL. — This  account  includes  the  cost  of  all  fuel  used  in  the  power 
houses,  with  transportation  charges  on  the  same. 

8.  LUBRICANTS   AND   WASTE  FOR    POWER   HOUSES. —  Oils,   greases, 
tallow  and  waste  for  use  in  the  power  houses,  for  engines,  shafting, 
dynamos,  pumps,  etc. 

MAINTENANCE  OF  WAY  AND  BUILDINGS. 

1.  REPAIRS  OF  ROADWAY  AND  TRACK. — This   account  includes  all 
expenditures  on  account  of  the  road-bed  and  track,  except  the  cost  of 
rails  and  ties  used,  and  the  cost  of  repairs  and  renewals  of  paving  and 
the  supplementary  wire.     It  includes  tracks  laid  in  buildings,  yards, 
on  turn-tables,  wharves,  and  over  bridges ;  wages  of  roadmasters,  track 
foremen,    laborers,    watchmen,   and   others,    while   engaged  in   track 
repairs  and  renewals.     It  includes  cleaning,  oiling  and  sanding  track, 
repairs  and  renewals  of  drains  under  the  track,  repairs  and  renewals 
of  planking  ove'r  bridges,  repairs  and  renewals  of  frogs  and  switches, 
joint  fastenings,  etc.,  etc.,  removing   snow  and  ice,   repairs  of  snow 
plows  and  sweepers.     It  also  includes  repairs  of  rails  and  all  work  on 
rails,  cutting  and  drilling,  except  drilling  for  tie  wires;  also  labor  ex- 
pended in  taking  up  track.     The  cost  of  tools,    implements  and  all 
supplies  used  in  connection  with  the  track  is  included  in  this  account. 
The  expense  of  removing  snow  and  ice,  with  the  cost  of  repairs  on 
snow  plows  and  sweepers,  may  be  made  a  separate  account  if  so  de- 
sired, but  comes  under  the  head  of  Maintenance  of  Way. 

2.  RENEWALS  OF  RAILS. —This  account  includes  the  cost  of  new  rails 
laid  in  the  track,  with  the  transportation  charges  on  the  same,  less 
the  value  of  old  rails  taken  up.     The  expense  of  loading,  unloading, 
drilling,  cutting,  laying  and  repairing  rails  is  not  included  in  this  account. 

3.  RENEWALS  OF  TIES.— This  account  includes  the  cost  of  new  ties 
laid  in  the  track  and  the  freight  on  the  same.     The  expense  of  loading, 
unloading  and  laying  ties  is  not  included  in  this  account. 

4.  REPAIRS  AND  RENEWALS  OF  PAVING.— This  account  embraces  all 
expenditures  on  account  of  the  paving.     It  includes  the  cost  of  paving 
blocks  and  sand  and  the  cost  of  transportation  of  the  same ;  the  wages 
of  pavers,  laborers  and  others  engaged  in  repairs  and  renewals  of  pav- 
ing; also  the  cost  of  tools  and  other  supplies  for  the  same  work.     The 
expense  of  taking  up  and  relaying  paving  when  necessitated  by  the  re- 
pairs on  the  road-bed,  the  track  and  the  supplementary  wire  is  not 
chargeable  to  this  account,  but  to  the  account  for  which  such  expense 
was  incurred. 

25 


386  THE   ELECTRIC    RAILWAY. 

5.  REPAIRS  AND   RENEWALS  OF  THE  SUPPLEMENTARY  WIRE. — This 
account  includes  all  expenditures  on  account  of  the  supplementary 
wire  and  its  connections.     It  includes  the  cost  of  the  wire,  tie  connec- 
tions, channel  pins,  solder,  and  other  supplies,  also  tools  and  imple- 
ments used  in  connection  with  the  work  of  repairing  the  supplementary 
wires;  wages  of  solderers,   laborers  and   others   engaged  upon   this 
work.     The  expense  of  drilling  rails  for  channel  pins  and  tie  wire 
rivets  is  also  chargeable  to  this   account.     Expense  on  the  supple- 
mentary wires,  necessitated  by  the   taking  up  of  rails,  ties,    switches, 
frogs,  etc. ,  is  not  chargeable  to  this  account,  but  to  repairs  of  roadway 
and  track.     Expense  on  the  supplementary  wires  necessitated  by  the 
taking  up  or  laying  of  paving  should  be  charged  to  the  account  of 
paving. 

6.  REPAIRS  AND  RENEWALS  OF  BUILDINGS,  DOCKS  AND  WHARVES. — 
This  account  includes  the  cost  of  repairs  and  renewals  of  all  buildings, 
docks  and  wharves  and  of  the  stationary  fixtures  and  furniture  of  the 
same  not  otherwise  provided  for ;  car  houses  and  sheds,  store  houses, 
car  shops,  repair  shops,  blacksmith  and  machine  shops,  power  houses, 
coal  sheds  and  bins,  stations,  etc.,  etc.     Repairs  of*  pits  in  car  houses 
and  shops,  cranes  in  power  houses  and  coal  sheds,  etc.,  are  embraced 
in  this  account.     Repairs  of  tracks  in  buildings  and  on  wharves  are 
not  chargeable  to  this  account. 

7.  REPAIRS  AND  RENEWALS  OF  POLES  AND  OVERHEAD  LINES. — This 
account  includes  the  cost  of  repairs  and  renewals  of  poles  and  brackets, 
with  trolley,  span,  guard  and  feed  wires,  with  all  appliances  for  sus- 
pension and  insulation  of  the  same. 


MAINTENANCE    OF    EQUIPMENT. 

i.  REPAIRS  OF  CARS. — This  account  includes  the  cost  of  all  repairs 
on  car  bodies,  painting,  varnishing,  upholstering,  relettering  cars 
and  car  signs ;  repairs  and  renewals  of  the  trucks,  brakes,  brake  shoes, 
axle  boxes,  springs,  track  brushes,  snow  scrapers,  pilots,  sand  boxes, 
etc. ;  repairs  and  renewals  of  wheels  and  axles.  The  cost  of  new  cars 
taking  the  place  of  old  to  make  the  number  good  is  also  chargeable 
to  this  account.  On  roads  using  both  motor  and  tow  cars  it  is  ad- 
visable to  keep  each  kind  separately. 

2.  REPAIRS  OF  ELECTRICAL   EQUIPMENT. 

A.  Armatures  and  Fields.— This  account  includes  the  cost  of  repairs 
and  renewals  of  armatures  and  fields,  labor  of  removing  from  the  cars 
those  damaged,  also  cost  of  replacing  them  and  making  all  connec- 
tions.    New  armatures  and  fields  put  in  to  take  the  place  of  old,  to 
keep  the  number  good,  are  chargeable  to  this  account. 

B.  Gears  and  Pinions.— This  includes  the  cost  of  repairs  and  renewals 
of  gears  and  pinions,  labor  removing  and  replacing  in  the  cars;  also 


APPENDIX    D.  387 

the  cost  of  new  gears  and  pinions  put  in  to  take  the  place  of  those 
damaged  or  destroyed. 

C.  Trolleys. — This  account  embraces  all   repairs  and   renewals   of 
trolleys  and  their  parts,  labor  of  taking  off  and  replacing,  and  the  cost 
of  new  trolleys  replacing  those  damaged  or  destroyed. 

D.  Sundry  Repairs. — This  account  embraces  the  repairs  of  motors 
and  their  connections,   excepting  armatures  and  fields,  gears  and  pin- 
ions, and  trolleys.     It  includes  the  repairs  of  wiring,  cables,  repairs 
and    renewals    of    lightning    arresters,    reversing    switches,    cut-out 
switches,  main  motor  switches,  rheostats,  and  pans,  brush  holders, 
motor  pans,  etc.,  etc. 

3.  REPAIRS  OF  STEAM  PLANT. — To  this  account  should  be  charged 
all  repairs  and  renewals  of  the  steam  plant  in  the  power  house,  includ- 
ing the  boilers,  engines,  pumps  and  shafting,  repairs  and  renewals  of 
belts,  piping,  steam. fitting,  etc.,  etc. 

4.  REPAIRS  OF  ELECTRICAL  PLANT. 

A.  Dynamos. — Repairs  and  renewals  of  dynamos  and  their  parts; 
armatures,  fields,   pulleys,  commutators,   oilers,   bearings  and  boxes, 
brush  holders,  etc.,  are  all  chargeable  to  this  account;  also  labor  re- 
moving and  replacing  damaged  parts. 

B.  Switchboard  Equipment. — Repairs  and  renewals  of  the  switchboard 
equipment  are  charged  to  this  account,  such  as  repairs  and  renewals 
of  station  switches,  rheostats,  circuit  breakers,  ammeters,  wiring  and 
connections. 

5.  TOOLS   AND   MACHINERY. — Repairs    and   renewals   of  tools  and 
machinery,  shafting,  boilers,   engines,  etc.,  in  the  shops  of  the  com- 
pany; also  cost  of  lubricants  for  the  same.     Small   tools   (not  shop 
fixtures)  are  chargeable  to  the  account  most  benefited  by  them. 

6.  MISCELLANEOUS  EXPENSE. — To  this  account  should  be  charged  all 
miscellaneous   expense  of  maintenance   of  equipment  not  otherwise 
provided  for. 

CONSTRUCTION   AND    EQUIPMENT    EXPENSES. 

Too  much  care  cannot  be  exercised  in  charges  to  this  account. 
Nothing  should  be  charged  to  construction  and  equipment  except  that 
which  adds  to  the  first  or  original  cost  of  the  property. 

1.  SUPERINTENDENCE  AND  GENERAL  EXPENSE. — Salaries  of  superin- 
tendent  of  construction,    assistants,  wages  of  clerks  and  others  em- 
ployed in  the  offices  of  this  department.     Expense  of  the   office,  fur- 
niture,   fuel,  lighting,  supplies  for  office,  miscellaneous  and  personal 
expense  of  superintendent  and  assistants  while  on  business.     Includes 
stationery  and  printing  for  this  department. 

2.  ENGINEERING. — Wages  and  expenses  of  engineers  and  draughts- 
men on  preliminary  work  and  construction. 


388  THE   ELECTRIC    RAILWAY. 

3.  RIGHT  OF  WAY. — Salaries  and  expenses  of  right-of-way  agent, 
together  with  payments  for  rights  of  way,  easements,  franchises,  pay- 
ments for  land  for  buildings,  shops,  etc. 

4.  BUILDING  CONSTRUCTION. — Cost  of  buildings — car  houses,    sta- 
tions, offices,  store  houses,  power  house,  repair  shops,  wharves,   coal 
sheds,  etc.,  etc. ;  also  furniture  and  fixtures  for  the  same. 

5.  TRACK  AND  ROADWAY  CONSTRUCTION. — Includes  the  expense  of 
grading,  surfacing,  ballasting,  ditching  and  paving ;  the  cost  of  rails, 
rail  chairs,  ties  and  stringers,  tie  rods,  joint  fastenings,  track  spikes, 
frogs  and  switches,  supplementary  wire,  tie  wires,  channel  pins,  solder 
and  miscellaneous  track  material;  also  the  cost  of  distributing  and 
laying  the  same,  with  the  supplementary  wire  and  its  connections. 

6.  OVERHEAD  CONSTRUCTION. — Cost  of  poles  and  setting,  putting  up 
trolley,  feeder  and  guard  wires,  including  cost  of  wire  and  all  devices- 
for  overhead  construction. 

7.  CAR  EQUIPMENT. — Cost  of  cars  built  or  purchased,  including  the 
cost  of  trucks,  motors,  upholstering,  painting,  lettering,  varnishing, 
etc. 

8.  SNOW  PLOWS  AND  SWEEPERS.— Cost  of  snow  plows  and  sweepers 
built  and  purchased,  including  the  electrical  equipment  of  the  same. 

9.  POWER   STATION   EQUIPMENT. —  Cost   of    steam    plant,    engines, 
boilers,  pumps,  piping,  shafting  and  belting,  dynamos  and  switchboard 
equipment,  together  with  installation  of  the  same. 

10.  TOOLS  AND  MACHINERY. — Cost  of  tools  and  machinery  for  repair 
shops,  car  houses,  etc. ,  and  expense  of  setting  and  placing  in  running 
order. 

11.  IMPROVEMENTS  AND  BETTERMENTS.— All  expenditures  which  im- 
prove the  original  plant,  and  of  which  a  portion  should  be  charged  to- 
operating  and  a  portion  to  construction  expenses. 

ACCOUNTING   FORMS. 
Form  A. 

Form  A  is  a  sheet  9^  inches  wide  by  12  inches  long,  and  printed  on 
one  side  only.  All  the  solid  lines  in  the  form,  as  shown  below,  both 
horizontal  and  perpendicular,  are  ruled  in  red  ink.  The  dotted  hori- 
zontal lines  are  all  faint  blue  ruled.  The  upper  set  of  dotted  lines  are 
crossed  over  each  side  of  the  double  perpendicular  lines  by  eleven 
perpendicular  heavy  blue  lines,  making  thereby  twelve  columns,  each 
set  of  twelve  columns  being  separated  by  double  perpendicular  red 
ink  hues.  The  figures  under  the  columns  entitled  Date  run  from  r 
:o  31,  inclusive.  The  space  above  the  double  horizontal  lines  at  the 
the  page  is  i#  inches;  the  space  devoted  to  Summary  of  Mile- 
age is  2^  inches  high.  The  dotted  lines,  nine  in  all,  are  faint  blue 

ied.     The  short  lines  at  the  bottom  of  the  page  are  printed  heavy 
black,  being  in  the  original  form  one  inch  long. 


APPENDIX    D. 


389 


FORM  A. 

Daily  account  of  trips  run  and  monthly  report  of  revenue  mileage  of 
Motor  Electric  Car  No 


Revenue  Motor  Trips. 

Revenue  Towed  Trips. 

Date.     | 

1 

2 

3 

29 

3° 

3i 

Total. 

Motor  trips  on  Route  N( 


SUMMARY  OF  MILEAGE. 

Towed  trips  on  Route  No © 


Total  motor  mileage, 


Total  towed  mileage, 


Form  C. 

Form  C  is  printed  on  a  four-page  sheet  14  inches  high  by  8^  inches 
wide.  The  width  of  each  column  of  the  first  page  appears  under  its 
respective  title,  the  Endorsement  taking  one-quarter  of  the  page,  and 
both  sections  entitled  Pay  Rolls  appear  on  the  first  page.  The  fol- 
lowing two  subdivisions  appear  on  the  second  page,  and  the  next  two 
on  the  third  page.  The  section  entitled  Earnings,  and  all  that  follow, 
are  on  the  fourth  page.  The  dotted  horizontal  lines  through  the  entire 
form  as  printed  are  ruled  faint  blue,  spaced  }£  inch  apart.  All  the 
solid  lines  are  ruled  in  red,  except  the  heavy  perpendicular  lines, 
which  are  ruled  dark  blue.  Each  of  the  four  sections  on  the  second 


390 


THE   ELECTRIC    RAILWAY. 


and  third  pages  is  given  half  a  page,  each  separate  item  being  placed 
on  a  single  line.  The  columns  are  uniform,  being,  on  the  second  and 
third  pages,  #  inch  and  i  inch  wide  alternately,  while  on  the  fourth 
page  they  are  i  inch  and  X  inch  wide  alternately.  On  all  three  pages 
there  are  four  sets  of  columns. 

FORM  C. 


RECAPITULATION. 
EARNINGS,  EXPENSES  AND  NET  EARNINGS. 


Motor 
Mile- 
age. 

Earnings. 

Expenses. 

Per  cent, 
of  Exp. 
to  Earn. 

Net 
Earnings. 

Exp. 
per  Car 
Mile. 

Exp. 
per 
Pass. 

Month  of  

i 

r 

r 

i 

)'/4 

K 

% 



:;. 

Decrease.... 

::::::::  :r 

:: 

EARNINGS,  EXPENSES  AND  NET  EARNINGS. 
Current  Year  Compared  with  Corresponding  Period  of  Last  Year. 


Motor 
Mile- 
age. 

Earnings. 

Expenses. 

Per  cent, 
of  Kxp. 
to  Earn. 

Net 
Earnings. 

Exp. 
per  Car 
Mile. 

Exp. 

per 
Pass. 

Jan.  ist  to  

i 

,     r, 

\ 

'   1 

'    1* 

y\ 

% 

Increase  
Decrease  

::::::!::[: 

:::::::'::l: 

:::::::[: 

::::::::{ 



PAY  ROLLS. 


18.. 

18.. 

Increase. 

Decreas 

General  Office  

' 

'•4 

i 

i 

1 

'. 

i 

Motor  Men  and  Conductors  
Power  House  

Maintenance  of  Roadway  and  Track  

"    Equipment  

Total 

] 

APPENDIX    D. 


391 


PAY  ROLLS. 
Current  Year  Compared  with  Corresponding  Period  of  Last  Year. 


18.. 

18.. 

Increase 

Decrease 

1 

% 

1 

K 

i 

Maintenance  of  Roadway  and  Track  

Total 

i 

GENERAL  EXPENSES. 

Salaries  of  General  Officers  
"           "  Clerks  in  General  Offices 

K 

:_- 

% 

y4 

y^ 

Jl   K 

i 

• 

••  

- 

:: 

Contingent  Expenses  

Total 

\ 

TRANSPORTATION  EXPENSES. 
far  Service 

1 



Lubricants  and  Waste  for  Cars  ! 
Electric  Supplies 

Wrecking  

Fuel  
Lubricants  and  Waste  for  Power  House  

Total 

DETAILS  OF  EXPENSE  ACCOUNT. 


MAINTENANCE  OF  WAY  AND  BUILDINGS. 

|  

"        "    Ties                                                             

Repairs  and  Renewal  of  Paving  

**          "              u              "  O  *      h       H  T  inf* 

Total, 

1 

392 


THE    ELECTRIC    RAILWAY. 
DETAILS    OF    EXPENSE   ACCOUNT—  Contimied. 


MAINTENANCE  OF  EQUIPMENT. 


Repairs  of  Cars 

"          "  Electrical  Equipment.. 
"         "  Armatures  and  Fields. 

"         "  Gears  and  Pinions 

"         "  Trolleys 

Sundry  Repairs 

Repairs  of  Steam  Plant 

"         "  Electrical  Plant 

Dynamos 

Switch  Board  Equipment 

Tools  and  Machinery 

Miscellaneous  Expenses 

Total, 

Comparative  Statement  of  Earnings \  Expenses,  Net  Earnings  and  Mileage. 

Statistics 

and  for  Current  Year  Compared  with  Corresponding  Period  of  Last  Year 

EARNINGS. 

Increase.    Decrease. 

Passenger 

Tickets 

Mail 

Miscellaneous  . 

Tot 

EXPENSES. 

Increase.    Decrease 

I 

Transportation 

Maintenance  of  Way  and  Buildings 
"    Equipment 

Total, 

MILEAGE  STATISTICS. 

18..       ij  Increase.   Decrease. 

Double  Motor  Box. 
Single  "  "  . 
Double  "  Open 
Single 

Tow  Car 

Long  Box 

"      Open 


Total, 


APPENDIX   D. 


393 


EARNINGS. 
Current  Year  Compared  with  Corresponding  Period  of  Last  Year. 


18.. 


Increase. 


Decrease. 


Passenger I I 

Ticket 

Mail ! I I  I. 

Miscellaneous | I.. 

Total,  | 

EXPENSES. 
Current  Year  Compared  with  Corresponding  Period  of  Last  Year. 

Increase.    Decrease 

General 

Transportation 

Maintenance  of  Way  and  Buildings 
"    Equipment 

Total, 

MILEAGE  STATISTICS. 
Current  Year  Compared  with  Corresponding  Period  of  Last  Year. 

Increase.    Decrea 

'  ' 

Double  Motor  Box. . . 
Single  "  "  .. 
Double  "  Open. 
Single  "  "  . 

Tow  Car 

Long  Box 

"      Open  


Total, 


Form  D. 

Form  D  is  a  sheet  12  inches  wide  by  17  */  inches  long,  and  is  printed 
on  both  sides,  Form  E  being  on  the  reverse  side,  so  that  when  the 
book  lies  open,  the  Material  £7$^  page  is  opposite  the  Material  Received 
page.  Single  red  ink  perpendicular  ruled  lines  divide  the  columns, 
and  the  width  of  each  column  is  given  under  its  respective  title. 
There  are  59  horizontal  faint  blue  lines  on  the  page.  The  height 
above  the  double  horizontal  red  lines  at  the  top  is  1 1/2  inches. 

FORM  D. 
MATERIAL  USED. 


Charge          Where  To  whom 

unt-     i    account.  used.  delivered. 


394 


THE    ELECTRIC    RAILWAY. 


Form  E. 
For  explanation,  see  remarks  descriptive  of  Form  D. 


FORM  E. 
MATERIAL  RECEIVED. 

Date. 

Kind  and  amount 
of  material. 

Price. 

Amount. 

From 
whom. 

How 
received. 

Bill 
Checked. 

*" 

3. 

% 

X 

* 

« 

* 

« 

Form  F. 

Form  F  is  a  slip  7%  inches  wide  by  4  inches  high,  and  printed  on 
one  side  only.  The  word  Foreman  is  at  the  foot  of  the  slip  on  which 
appears  8  lines  running  the  full  cross-width  of  the  paper;  with  a 
double  line  above  and  below  the  single  lines.  There  is  no  colored 
ruling  on  the  slip. 


Storekeeper: 


Please  furnish  the  following  material  for  use  on 


Foreman. 


Form  P. 

Form  P  is  a  book  4  inches  wide  by  6^  inches  long,  bound  with  a 
stout  paper  cover.  It  contains  six  sheets,  which  when  folded  in  the 
centre  make  a  book  of  24  pages. 

The  blank  space  above  the  double  ruled  line  at  the  top  of  the  page 
is  about  i  inch  high. 

The  widths  of  the  several  columns  appear  under  their  respective 
titles.  The  dotted  lines  in  the  form  below  are  ruled  faint  blue  in  the 
•original,  and  are  spaced  %  inch  apart,  of  which  there  are  19  in  all. 
All  the  solid  lines  are  ruled  in  red. 


TIME  WORKED  by.... 
for  week  ending 


Occupation, 

Rate  per  day  or  month,  $. 


Specification  of  Work. 

a 

•^ 

CO 

| 

i 

•d 

o 

£ 

H 
^ 

£ 

1 

£ 

•r. 

?, 

IS 

£.§ 

Amount 

Charge 

Account. 

3^  in. 

'4 

'4 

YA, 

', 

K 

'.» 

* 

?i 

% 

X 

3 
16 

3. 

16 

!•-- 

• 

Total, 

APPENDIX    D. 


395 


On  the  title-page  of  cover  appears  the  following,  properly  spaced, 
of  course : 

TIME   BOOK. 


week  ending. . , 


certify  the  time  and  rates  as  shown  herein  are  correct. 


Foreman. 


On  the  last  page  of  cover  appears  the  following : 


The  time  of  each  man  must  be  entered  in  this  book  at  the  close  of 
each  day's  work,  and  the  book  forwarded  to  the  General  Office  at  the 
end  of  each  week.  Do  not  fill  in  the  last  two  columns. 

Form  G. 

Form  G  is  printed  on  a  sheet  8  inches  wide  by  7  inches  high.  An 
endorsement  appears  on  the  back  of  the  sheet.  All  of  the  solid  lines 
in  the  following  form  are  ruled  .in  red  ink,  and  the  width  of  the  col- 
umns appears  under  each  heading.  There  are  22  ruled  lines,  in  faint 
blue,  on  the  sheet,  and  the  height  of  the  space  at  the  top  is  i  inch. 

FORM  G. 

Department. 

Foreman's  report  of  material  used  in  month  of ,     189. . 


Date. 

Location  and  de- 
scription of  work. 

Quantity  and  kind 
used. 

Foreman  \ 
columns 

vill  leave  these 
blank. 

i  in. 

2K 

*X 

Cost. 

Total  cost. 

X      IX                KIM 

On  the  back  of  Form  G  appears  the  following  endorsement : 

Department. 


Foreman's  Report  of  material  used 

in  month  of ,      189. . 

I  certify  the  within  report  to  be  correct. 

Foreman, 

Foreman  will   keep  a   careful  and  accurate  account   of  all  materials 
used  or  issued,  and  make  report  of  same  on  this  blank  daily. 

Form  S. 

Form  S  is  a  sheet  9^  inches  wide  by  12  inches  long,  and  is  printed 
on  one  side  only.     There  are  22  horizontal  lines  on  the  page,  ruled 


396  THE   ELECTRIC    RAILWAY. 

faint  blue.     The  lines  that  appear  in  the  following  printed  form  are 
red.     The  width  of  each  column  appears  under  its  title. 

FORM  S. 

THOMSON-HOUSTON  ELECTRIC  COMPANY,  RAILWAY  DEPARTMENT. 
On  account  West  End  Street-Railway  Company. 


Daily  Report  of  Condition  of  Motor  Car 

rRr, 

Div   Clerk 

Car 

Number. 

In  Shops. 

Out  Shops. 

Remarks. 

Date. 

Time. 

Date. 

Time. 

iK  in. 

j 

' 

' 

1 

4 

APPENDIX  E. 


CONCERNING   LIGHTNING   PROTECTION. 

BY    PROFESSOR    ELIHU    THOMSON. 

The  discharges  of  lightning  as  affecting  railway  and  other  installa- 
tions may  be  divided  into  four  classes. 

The  first  and  probably  the  most  dangerous  of  all  discharges  of 
lightning  is  a  stroke  falling  on  the  line  from  the  clouds  and  seeking 
ground  through  the  conductor  itself  and  through  the  cars  connected 
to  it. 

Second,  inductional  discharges  produced  by  discharges  in  the 
clouds  moving  in  a  parallel  or  approximately  parallel  direction  of  the 
line  of  the  track.  These  discharges  are  of  course  less  severe  than  the 
former,  but  may  introduce  complicated  actions  owing  to  the  induction 
on  the  track  being  the  same  in  direction  as  that  on  the  line. 

Third,  leakage  discharges,  which  may  be  of  the  nature  of  lateral 
branchings  from  a  portion  of  earth  which  has  received  a  heavy  stroke, 
and  which  lateral  branchings  will  of  course  divide  themselves  over  the 
return  conductors,  and  may  reach  the  station. 

Fourth,  electrostatic  induction  from  cloud  layers,  which  when  dis- 
charged of  course  give  rise  to  changes  of  electric  potential  in  all 
metallic  masses  under  them.  This  latter  is  perhaps  the  most  common 
action  occurring  during  thunder  storms  and  the  one  which  gives  rise  to 
the  minor  discharges  tending  to  equalize  the  potentials  over  the  sys- 
tem and  which  have  to  be  guarded  against  by  the  arrester  devices. 
The  character  of  the  discharges  which  reach  the  line  may  be  that  of  a 
sudden  or  instantaneous  action  or  may  occupy  a  slight  period  of  time, 
and  may  therefore  be  characterized  as  slower  inductive  discharges. 

As  to  the  character  of  the  discharge,  of  course  the  more  sudden  and 
violent  the  action  the  more  dangerous  it  is  likely  to  be  to  the  insulation 
of  the  plant.  The  slower  discharges  having  time  to  reach  an  equaliza- 
tion are  not  so  apt  to  produce  those  great  differences  of  potential 
between  one  point  and  another  which  lead  to  perforation  of  insulation, 
etc.  It  is  questionable,  indeed,  whether  any  devices  whatever  will  be 
sufficient  to  take  care  of  the  plant  and  avoid  all  damage  where  the 
lightning  falls  directly  on  the  trolley  line. 

The  only  safeguard  in  such  a  case  is  to  seek  out  the  exposed  sections 
of  such  a  line — places,  for  example,  where  the  line  passes  over  high 
ground  and  stands  alone  unsurrounded  by  metallic  wires  or  high  or 

397 


398  'THE  ELECTRIC  RAILWAY. 

metallic  buildings— and  protect  such  places  by  the  introduction  of 
lightning  rods  on  the  suspending  poles  run  into  the  ground  and  extend- 
ing high  enough  above  the  general  trolley  line  to  divert  any  discharge 
therefrom. 

It  is  pretty  safe  to  say  that,  so  far  as  the  station  itself  goes,  damaging 
discharges  will  mostly  enter  on  the  feeder  lines;  though  discharges 
which  do  damage  may  of  course  come  in  on  the  ground  return,  espe- 
cially if  the  stroke  should  fall  to  the  ground  not  far  away  from  the 
station  and  if  the  ground  itself  be  not  of  a  very  moist  and  conducting 
character.  It  is  conceivable  that  in  the  case  assumed  the  discharge 
from  cloud  to  earth  may  find  the  earth  so  poor  a  conductor  as  to  seek 
the  rails  and  scatter  itself  along  them.  As  the  trolley  line  and  the 
whole  structure  of  the  electrical  installation  is  practically  only  a 
metallic  extension  of  the  rail  conductor,  there  may,  of  course,  be  dan- 
ger from  the  current  scattering  itself  over  the  whole  system  and  break- 
ing down  the  insulation  in  its  path.  The  remedies  which  seem  most 
applicable  to  the  case  of  lightning  discharges  reaching  the  stations  by 
the  feeders,  whether  these  discharges  are  of  an  inductive  character  or 
direct  strokes,  are  the  employment  of  lightning  arresters  on  the  feeder 
lines  in  such  a  manner  that  the  earth  connection  from  them  is  as  short 
and  direct  and  of  as  little  self-induction  as  possible. 

To  this  end  each  station  should  have  heavy,  broad  ground  connec- 
tions, such  as  good-sized  piping  led  to  the  best  metallic  grounding  con- 
ductor within  reach,  arid  this  ought  to  be  as  short  as  possible,  the 
feeder  lines  being  brought  down  to  it  rather  than  that  it  be  brought 
up  to  the  feeders.  The  type  of  arrester  which  seems  to  be  the  best 
adapted  to  use  here  is  one  in  which  the  spark  gap  is  as  small  as  it  can 
be  made  safely  and  in  which  there  is  a  means  for  disrupting  or  blow- 
ing outthe  arc,  which  will,  of  course,  form  to  ground  and  short  circuit 
the  system  when  a  lightning  discharge  takes  place. 

There  should  also  be  a  heavy  self-induction  coil  on  the  dynamo  side 
of  this  arrester,  placed  in  such  a  manner  that  it  tends  to  divert  any  dis- 
charge to  ground  and  oppose  a  reaction  of  great  force  to  any  heavy 
discharge  moving  in  the  direction  of  the  dynamo.  A  self-induction  of 
this  kind  is  also  useful  in  preventing  the  short-circuiting  action  through 
the  arrester  from  attaining  undue  proportions  in  an  instant. 

It  acts,  in  other  words,  to  secure  a  little  time  for  the  blowing-out 
action  to  be  accomplished  before  the  current  in  the  ground  branch  has 
become  equivalent  to  a  short  circuit  on  the  system.  It  would  seem  in 
all  cases  preferable  wherever  the  grounded  dynamo  terminal  exists  to 
bring  that  terminal  back  to  the  ground  plate  of  the  arrester  and  make 
the  ground  at  that  spot. 

In  this  way  the  spark  gap  in  the  lightning  arrester  becomes  a  shunt 
to  the  dynamo  terminals,  the  gap  possesses  the  less  opposition  to 
currents  going  to  ground,  and  this  tends  to  divert  the  discharges  from 
the  dynamo  loop.  A  counter-inductive  protector  should  be  introduced 


APPENDIX    E.  399 

into  the  circuit  to  protect  the  dynamo  by  the  counter-inductive  effect 
set  up  in  it  by  the  discharge  coming  to  earth.  This  arrangement  of 
devices  in  ordinary  cases  it  would  seem  ought  to  be  sufficient,  and 
it  is  only  conceivable  that  in  the  case  of  very  heavy  discharges  they 
might  not  serve  their  purpose  fully. 

A  station  constructed  with  an  iron  framework  which  in  itself  was 
made  the  ground  for  the  arrester  would,  of  course,  be  an  ideal  arrange- 
ment. An  open  iron  cage  or  framework  of  iron  around  the  dynamo 
would  be  an  addition  of  value,  the  openings  in  the  cage  being  made 
of  convenient  size,  such  as  a  foot  square,  and  therefore  made  so  as  not 
to  interfere  with  the  manipulation  of  the  machine.  In  case  such  a  cage 
were  employed  it  should  have  a  spark  gap  and  blow-out  device  be- 
tween each  terminal  leading  from  the  commutator  to  the  cage.  The 
self-induction  of  the  blowing-out  apparatus  should  be  on  the  side  of 
the  dynamo  circuit.  This  arrangement  might  be  an  inconvenient  one 
to  adopt  in  stations,  and  while  effective,  the  objections  to  it  might  be 
sufficient  to  rule  it  out. 

An  effective  substitute  for  such  an  arrangement  may  be  to  use  a 
spark  gap  between  the  field  magnet  and  the  conductors  leading  to  the 
commutator  brushes  of  the  dynamo,  so  that  a  stroke  tending  to  jump 
through  the  insulation  of  the  armature  to  the  core  would  be  prevented. 
The  principle  of  this  arrangement  would  be  to  establish  a  weak  point, 
as  it  were  an  artificial  weak  point,  in  insulation,  between  the  iron  frame 
of  the  dynamo  and  its  wiring — such  that  the  discharge  on  reaching  the 
dynamo  from  either  terminal  would  be  led  to  take  its  path  across  the 
discharge  plates  (or  weak  point  provided)  instead  of  through  any  of  the 
insulation  of  the  machine,  which  insulation  should,  of  course,  be  su- 
perior at  every  point  to  the  insulating  power  of  the  spark  gap. 

This,  it  would  seem,  ought  to  be  a  very  effective  arrangement  in 
saving  injury  to  dynamos,  and  if  its  action  could  be  coupled  with 
self-induction  in  the  lines  beyond  the  spark  gap  on  the  dynamo  side, 
of  course  the  effectiveness  would  be  increased. 

There  still  remains  the  condition  of  the  machine  acting  as  a  con- 
denser, taking  in  a  certain  static  discharge,  suddenly  reaching  the 
limit  of  its  capacity,  backing  up  the  discharge  and  causing  perforation — 
an  action  which  occurs  in  condensers  and  frequently  leads  to  their 
destruction  by  perforation.  A  counteracting  condenser  might  possibly 
be  introduced,  which  would  cause  the  spark  gap  to  be  called  into 
service  as  the  weak  point,  instead  of  leaving  it  to  the  condensing 
action  of  the  machine.  If  this  reasoning  be  correct,  and  it  appears 
that  it  must  be,  then  the  spark  gap  should  be  supplemented  by  a 
certain  amount  of  condenser  surface  adjoining  it,  and  leading,  as  it 
were,  the  discharge  in  a  sort  of  blind  alley  for  building  up  the  po- 
tential across  the  spark  gap. 

As  to  continuance  of  the  use  of  the  pipe  arrangements  for  dis- 
charges tending  to  reach  earth  at  stations,  it  would  seem  that  if  the 


400  THE   ELECTRIC    RAILWAY. 

precautions  above  mentioned  were  caried  out  consistently  there  would 
be  no  real  reason  for  the  pipe  being  retained,  though  without  question 
it  does  no  harm  if  present,  and  may  do  some  good. 

Concerning  the  protection  of  dynamos  from  discharges  reaching 
them  from  a  ground  line,  it  would  seem  that  the  precautions  above 
stated  would  be  sufficient  to  protect  them,  the  greater  danger  being 
from  the  discharges  reaching  the  machines  from  the  overhead  lines, 
for  which  all  the  precautions  are  taken ;  while  the  discharges  coining 
from  earth  would  necessarily  be  of  rather  lower  intensity,  and  with  the 
device  of  the  spark  gap  attached  to  the  dynamo  it  would  seem  that 
these  discharges  would  not  necessarily  puncture  the  insulation. 

It  may  be  well  to  reiterate  here  that  the  best  station  arrangement 
would  be  one  constructed  of  an  iron  framework  connected  to  the 
ground,  and  it  is  further  to  be  understood  that  if  the  station  be  itself  ex- 
posed to  strokes  of  lightning  none  of  the  wiring  leading  from  the  station 
overhead  should  exceed  in  height  the  highest  point  of  the  station 
which  has  a  conductor,  but  that,  on  the  other  hand,  a  solid  conducting 
rod  should  be  placed  in  connection  with  the  framework  of  the  station 
and  pass  upward  to  a  sufficient  height  to  cover  electrically,  or  at  least 
protect  from  discharges,  a  considerable  extent  of  area  of  the  surround- 
ing territory.  This  would  prevent  any  lightning  stroke  falling  on  the 
lines  very  near  the  station,  the  object  being  to  interpose  as  much  of 
the  self-induction  of  the  lines  as  possible  between  the  point  of  stroke 
and  the  station. 

Whether  the  lightning-arrester  devices  be  put  upon  the  feeders  or 
upon  the  wires  leading  to  the  dynamo  separately  does  not  seem  to 
matter  very  much.  This  remark  applies  to  the  general  lightning 
arresters  which  are  applied  to  the  line's  entering  the  station.  If  applied 
to  the  feeders  alone  it  would  seem  to  be  sufficient  when  supplemented 
by  the  dynamo  spark  gap  shunting  arrangements  above  described.  As 
to  the  line  protection,  it  is  recommended  that  a  survey  of  the  trolley 
line  be  made  in  relation  to  the  chances  of  its  being  struck  by  lightning, 
•or  in  relation  to  its  exposure  to  cloud  effects  directly.  Note  if  it  should 
pass  over  a  hill  more  or  less  open  and  which  is  not  built  upon,  as  the 
line  would  be  exposed  in  an  exceptionally  favorable  way  to  strokes  of 
lightning,  being,  as  it  is,  an  excellent  conductor  of  electricity  and 
having  connection  to  ground  though  the  cars,  the  ground  also  being 
an  excellent  ground  on  account  of  the  extent  of  surface  covered  by  the 
connected  track. 

A  survey  of  the  line,  then,  should  discover  the  points  of  danger  from 
lightning  discharge,  and  precautions  should  be  taken  along  the  line 
and  particularly  at  those  points  liable  to  receive  strokes  of  lightning. 
This  protection  might  be  accomplished  by  connecting  the  foot  of  the 
poles  to  the  track  and  extending  the  poles  upward  by  a  rod  to  a  suffi- 
cient height  properly  to  protect  the  trolley  line.  It  is  not  to  be  ex- 
pected, however,  that  in  such  case  a  lightning  discharge  falling  upon 


APPENDIX   E.  40! 

any  pole  or  poles  would  fail  to  disturb  the  electrical  equilibrium  of  the 
line.  It  would,  indeed,  set  up  a  complicated  set  of  inductive  disturb- 
ances, if  it  did  not  leak  directly  to  the  line.  The  line,  on  account  of 
its  extent,  is  also  subject  to  extraordinary  inductive  actions  from 
cloud  discharges  and  to  electrostatic  induction  from  discharging  cloud 
masses. 

To  take  care  of  these  as  far  as  possible  there  should  be  placed  along 
the  line  a  number  of  grounded  lightning  arresters,  well  protected  from 
rain  so  as  to  avoid  leakage,  whereby  a  free  discharge  to  earth  may  be 
secured  without  allowing  the  line  current  to  follow.  These  arresters 
should  be  placed,  perhaps,  every  few  hundred  feet  apart  and  in  ex- 
posed locations  more  frequently.  They  should  be  found,  also,  at  every 
angle  of  the  line  where,  for  example,  the  line  takes  a  turn  at  right 
angles  or  in  some  other  direction,  the  inductive  action  of  the  clouds 
being  expected  to  accumulate  or  be  more  pronounced  at  such  places, 
and  therefore  more  apt  to  seek  earth  through  arresters  placed  at  these 
points. 

The  track  connections  of  the  line  may  of  course  be  regarded,  in  a 
sense,  as  extensions  of  the  general  conducting  system,  and  the  track 
itself  may  become  subject  to  inductive  disturbances  giving  rise  to 
trouble.  To  avoid  this  there  does  not  appear  to  be  any  better  means 
than  to  have  a  thorough  grounding  at  points  along  the  track,  such 
grounding  being  obtained  by  driving  tubes  into  the  ground,  iron  bars 
or  pipes,  until  a  water  stratum  is  reached,  or  by  making  attachments 
to  existing  pipes  leading  deep  into  the  ground. 

In  regard  to  the  protection  of  motors  on  cars,  the  problems  are  of  a 
similar  nature  to  those  existing  in  stations,  and  the  car  itself  may  be 
regarded  for  the  time  being  as  a  small  moving  station.  The  light- 
ning arresters  already  existing  may  be  retained  with  advantage  and 
arranged  so  that  they  become  efficient  spark  gap  shunts  of  the  motor. 
I  am  inclined  to  think  that  the  field-magnet  cores  in  motors  will  be 
best  protected  by  being  insulated  thoroughly  from  the  ground  as  well 
as  the  armature  cores,  as  by  that  means  there  will  be  less  tendency  for 
discharges  of  lightning  to  leave  the  wire  and  jump  through  the  iron  of 
the  machine.  Where  they  are  not  so  protected  by  being  insulated, 
that  is,  where  they  are  really  grounded,  it  would  seem  that  the  light- 
ning arresters  should  be  able  in  most  cases  to  take  care  of  the  motors. 

There  comes  in,  however,  in  this  connection  a  condenser  action 
between  the  field-magnet  coils  and  their  cores  and  between  the  arma- 
ture winding  and  its  core  which  might  divert  at  low  potentials  a  dis- 
charge insufficient  to  jump  the  spark  gap,  but  which  by  the  condenser 
action  existing  would  suddenly  give  rise  to  local  potentials  at  weak 
points,  breaking  through  the  insulation  and  spoiling  the  machine.  The 
only  remedy  available  seems  to  be  such  a  one  as  has  been  suggested 
for  the  dynamos,  to  establish,  as  it  were,  a  sort  of  blind  alley  for  the 
discharge,  and  force  it  to  leap  an  artificial  weak  spot  which  virtually 
26 


402  THE    ELECTRIC    RAILWAY. 

takes  the  place  of  the  insulation  between  the  winding  and  the  cores  of 
the  dynamo. 

Upon  this  point  experiments  are  needed  to  determine  just  what  the 
danger  is  and  how  to  meet  it.  I  am  inclined  to  think  that  here  again 
the  precautions  used  on  the  dynamo  would  be  effective,  that  counter- 
inductive  devices  of  simple  character  might  be  introduced  along  with 
the  ordinary  self-induction  of  the  arresters,  and  that  possibly  a  properly 
disposed  condenser  and  spark  gap  combined  might  be  introduced.  In 
fact  the  spark  gap  of  the  lightning  arrester  itself  might  be  utilized  as 
the  protecting  spark  gap,  especially  should  the  sparking  be  assisted 
by  the  condenser  action  just  indicated. 


APPENDIX  F. 


MOTORS     WITH     BEVEL     GEAR     AND     SERIES-MULTIPLE 
CONTROL   OF   MOTORS. 

SINCE  the  first  edition  of  this  book  was  published  there  have  been 
two  noticeable  improvements  in  the  street  railway  apparatus,  some- 
what antagonistic  in  their  result,  it  is  true,  but  decidedly  ingenious, 
and  each  having  an  important  field  of  action. 

One  of  these  is  the  improved  arrangement  of  bevel  gear  transmis- 
sion that  appears  in  the  Sperry  street  railway  motor  shown  in  Figs. 


FIG.  180.—  SPERRY  MOTOR  WITH  BEVEL  GEAR. 


1  80  and  1  8  1.  Its  essential  principle  consists  in  supporting  bevel  gears 
by  rigid  bearings  in  oil-tight  cases,  so  that  the  teeth  always  mesh 
accurately,  and  in  driving  one  or  both  of  these  gears  from  the  motor 
shaft  through  a  peculiar  form  of  flexible  clutch  which  seems  to  give 
excellent  results  in  practice.  It  is  shown  in  section  in  Fig.  181,  and 
needs  little  explanation,  consisting  as  it  does  of  a  pair  of  concentric 
spiders  with  projections  interlocking  through  rubber  cushions.  The 
outer  spider  has  teeth  inwardly  projecting  which  engage  a  toothed 
wheel  on  the  motor  shaft.  These  two  sets  of  teeth  admit  of  consider- 
able play,  which  is  permissible  because  there  is  no  marked  rubbing 
action  as  in  ordinary  gears  —  only  a  slight  sliding  and  steady  pressure. 
The  result  of  this  device  is  to  give  the  bevel-geared  street-car 
403 


404 


THE    ELECTRIC    RAILWAY. 


motor  a  much  better  place  in  the  art  than  it  has  ever  taken  before, 
rendering  it  possible  to  drive  both  axles  effectively  from  a  single 
motor  flexibly  supported.  In  certain  classes  of  work  the  advantage 
of  this  procedure  is  very  decided. 

The  other  improvement  noted  is  the  evolution  of  a  successful  series 
multiple  controller.  The  scheme  has  already  been  mentioned  and  some- 
what discussed ;  the  device  for  accomplishing  it,  however,  has  neces- 
sitated considerable  experimentation,  and  only  very  recently  has  it 
come  into  a  thoroughly  practical  form.  The  difficulties  that  had  to  be 
overcome  have  been  of  a  mechanical  rather  an  electrical  nature,  the 
details  hardly  being  suited  for  a  close  description  in  this  place.  The 
result  is,  that  the  motors  are  started  in 
series  and  thrown  into  multiple  as  part 
of  a  regular  speed-varying  regulation. 
By  thus  halving  the  electro-force  neces- 
sary to  be  generated  in  each  motor  it  be- 
comes possible  to  run  at  low  speeds,  with 
a  fair  degree  of  economy  and  without 
any  considerable  use  of  a  rheostat.  When 
high  speeds  are  desirable,  the  motors  are 
thrown  into  multiple  and  work  efficiently 
at  the  new  and  greater  speed.  The  net 
result  is  an  increase  of  general  efficiency 
of  probably  not  less  than  15  per  cent., 
with  a  corresponding  decrease  in  the  amount  of  power  necessary  to  be 
furnished.  This  is  most  emphatically  true  in  cases  where  a  large 
range  of  speeds  is  necessary,  as  in  roads  which  start  in  the  centre 
of  a  city  and  then  run  out  into  the  suburbs,  where  the  limitations  im- 
posed by  street  traffic  no  longer  exist. 

This  series  multiple  control  appears  to  avoid  most  of  the  difficulties 
which  have  heretofore  been  met  in  running  motors  economically  at 
low  speed.  It  may  be  mentioned  in  passing  that  this  method  would 
perhaps  find  a  very  favorable  application  in  enabling  the  gearless 
motors  to  be  used  with  a  much  greater  degree  of  economy  than  has 
been  heretofore  possible.  It  goes  without  saying  that  to  a  certain 
extent  the  series  multiple  control  decreases  the  advantages  to  be 
gained  from  the  use  of  a  single  motor,  by  raising  the  efficiency  of  the 
ordinary  combination  to  a  considerably  higher  point  than  heretofore. 
It  seems  probable,  however,  that  the  single  motor  geared  to  both  axles 
may  prove  very  serviceable  where  speeds  are  comparatively  uniform, 
as  in  certain  classes  of  tramway  work,  while  the  series  multiple  con- 
trol secures  for  street  railway  purposes  a  good  efficiency  at  very  widely 
varying  speeds. 


FIG.  181.— FLEXIBLE  CLUTCH. 


APPENDIX  G. 


METHOD    OF    MEASURING    INSULATION    RESISTANCE    OF 
OVERHEAD   LINES. 

IN  operating  an  electric  railway  plant  efficiently,  it  is  necessary 
that  the  loss  of  current  through  those  devices  supporting  the  over- 
head construction  should  be  a  minimum,  but  no  method  is  generally 
known  by  which  the  insulation  resistance  of  any  individual  insulator 


FIG.  182.— CONNECTIONS  FOR  MEASURING  INSULATION  RESISTANCE. 
Depress  key  i  to  measure  x.  Depress  key  2  to  measure  y. 

can  be  measured  without  removing  it  from  the  line.  Such  a  method 
is  here  described. 

Its  use  depends  upon  the  line  being  insulated  at  each  point  of  sup- 
port by  two  resistances  in  series,  of  which  there  is  commonly  one 
between  the  trolley  wire  and  the  span  wire,  and  the  insulation  of  each 
pair  of  poles  between  the  span  wire  and  the  ground. 

The  method  consists  in  measuring  the  voltage  from  trolley  wire  to 
405 


406  THE    ELECTRIC    RAILWAY. 

span  wire,  and  also  voltage  from  span  wire  to  ground.     These  meas- 
urements should  preferably  be  made  in  immediate  succession,  in  order 


To  determine  Leakage  on  Unea=R(2-x-y)  b=^(Z-x-y)  R  =72700 

MOO     20000     3000U     40000   '  50000    60000 ,0000  . i 


8QOOO  ohms 


Volts 
FIG.  183.— DIAGRAM  FOR  COMPUTING  INSULATION  RESISTANCE. 

that  the  voltage  of  the  line  shall  not  have  changed  in  the  mean  while. 
Indicating  the  respective  quantities  by  the  following  letters,  these 
equations  are  true : 

Let  R  equal  resistance  of  the  volt  meter. 

A  be  the  insulation  resistance  of  the  line  insulator. 
•B  pole  or  poles. 

x  measured  voltage  from  trolley  to  span  wire. 

y  span  wire  to  ground, 

trolley  wire  to  ground. 


For  rapidity  in  securing  these  results,  it  is  convenient  to  have  a  bam- 
boo pole  about  fifteen  feet  long  (weighing  only  about  18  oz.),  with 
two  metallic  hooks  on  the  upper  end  thoroughly  insulated  from  each 
other.  One  hook  should  be  caught  over  the  trolley  wire  and  the  other 
hook  over  the  span  wire,  and,  by  means  of  suitable  commutating  keys 
in  metallic  connection  with  each  of  these  hooks,  the  volt  meter,  and 
the  ground,  the  three  necessary  measurements  of  voltage  at  which 


APPENDIX   G.  407 

point  of  support  can  be  made  within  say  five  seconds.  The  adjoining 
cut  shows  the  diagrammatic  connections. 

These  measurements  can  be  systematically  entered  in  a  note-book, 
and  the  required  value  of  insulation  resistance  secured  without  calcu- 
lating, by  the  use  of  a  chart  with  radial  lines  drawn  thereon,  as  shown 
in  the  cut. 

By  proper  adding  or  dropping  of  ciphers  from  either  or  both  ordi- 
nates,  and  the  radial  lines,  results  can  be  secured  from  this  chart  with 
as  great  accuracy  as  if  it  were  drawn  on  a  scale  ten  or  one  hundred 
times  greater.  This  method  is  due  to  Mr.  Theodore  Stebbins. 


INDEX. 


ACCIDENT  charges,  320. 
Accumulator,  Alkaline  zincate,  243. 

alkaline  zincate,  Use  of,  244. 
Classes  of,  239. 
defined,  230. 

Efficiency  of  the,  in  electric  traction,  247-. 
Lead,  231 

lead,  Chemical  actions  in,  231. 
lead,  Electromotive  force  of  the,  231. 
lead,  Mechanical  defects  of  the,  242. 
lead.  Weight  of,  243. 
Life  of,  250. 
Accumulators,  Classification  of,  237. 

Effect  of  forced  output  on,  246. 
energy,  Losses  of,  in,  240. 
First  use  of,  for  traction,  344. 
Weight  of,  necessary  for  electric  traction,  245. 
Ampere-turns,  15. 
Anchoring  line,  375. 
Armature,  8. 

Diagram  of  connections  of,  25. 
Directly  connected,  95. 
shaft,  Manner  of  connecting,  87. 
Siemens,  18. 

Armatures,  Short  circuits  in,  197. 
Testing,  in  shop,  317. 

BATTERIES,  Primary,  7,  8. 
Belting,  183. 
Blasting,  Cost  of,  310. 
Boiler  scale,  192. 

scales,  Results  of,  193. 
Boilers,  174,  192. 

Proper  firing  of,  174. 

Means  for  feeding,  193. 

Water-tube,  174. 
Brakes,  Magnetic,  302. 
Brush,  Carbon,  188,  189. 

CAR  bodies,  Cost  of,  311. 

bodies,  Cost  of  maintenance  of,  318. 
houses,  152. 

Sixteen-feet,  work  per  car  mile,  245. 
wiring,  111. 
Cars,  Double-track,  179. 

open  and  closed,  Trucks  for,  107. 
409 


410 


INDEX. 


Chains,  Sprocket,  91. 
Circuit,  Field,  10. 

Working,  10. 

City  and  South  London  Railway,  273. 
Coal  per  car  mile,  213. 
Conductors,  Cost  of,  284. 

area  of,  Formula  for,  137,  139. 
Conducting  system,  Determination  of  area  of,  135. 

Economy  law,  285,  286. 
Coefficient,  Riding,  323. 

Traction,  124. 
Conduit,  Closed,  256. 

Modifications  of,  259. 

Siemens  &  Halske,  for  electric  railway,  256. 
slotted,  Commercial  importance  of  the,  258. 
Slotted,  for  electric  railways,  255. 
Slotted,  with  flexible  walls,  260. 
Conduits,  Modified  forms  of,  271. 
Connecting  rods  versus  gearing,  222. 
Current  rentals,  315,  316. 

density  of  induction  of  motor  field,  23. 


DROP  of  potential,  126. 

Average,  versus  total,  126,  140. 
Dynamo,  Action  of,  26. 

Compound-wound,  u. 
equipment,  Average  output  of,  213. 
first  used  as  a  motor,  339. 
Series- wound,  11. 
Shunt-wound,  9. 

Dynamos,  Connections  of,  for  railway  work  with  earth  return,  187. 
efficiency  of,  Commercial,  211. 
efficiency  of,  Electrical,  misleading,  211. 
Efficiency  of,  at  various  loads,  212. 
General  care  of,  188. 
Laws  of  operation  of,  8. 
Probable  faults  in,  195. 
railway,  Proper  care  of,  194. 
Running,  in  parallel,  189. 
self-exciting,  Invention  of  the,  339. 

EARNINGS  to  pay  5$,  322. 

Earth,  The,  considered  as  a  conductor,  138. 

Efficiency,  Central  station,  214. 

Effect  of  countershaft  on,  215. 
Motor  and  gear,  224. 
Electric  hoist,  The  first,  341. 

plant  for  railways,  Cost  of  a,  311. 

railway,  Accounting  rules  for,  382. 

railway  plants,  Irregular  output  of,  163,  164. 

traction  by  storage  batteries,  Commercial  efficiency  of,  247. 

traction,  Efficiency  of,  with  one  and  two  motors,  223. 
Electrics,  14. 
Electromotive  force,  Counter,  of  motors,  65. 


INDEX.  411 

Engine,  Compound,  39. 

and  dynamos,  Foundations  for,  176. 

Efficiency  of  an,  31. 

as  a  heat  converter,  210. 
Engines,  32. 
Engineer's  log-book,  190,  191,  381. 

FEED  wire,  Cost  of,  310. 
Feeders,  376. 

Cost  of  running,  137. 
Sub-feeders,  132. 

Field  circuits,  Arrangement  of,  for  commutation,  74. 
Commutation  of,  84. 
coil,  Magnetizing  of  a,  u. 
Strength  of,  15. 
Force,  Electromotive,  13,  15. 

Electromotive,  generated  by  unit  field  at  unit  speed,  20. 
Field  of,  9. 
Lines  of,  9. 

Magneto-motive,  as  relating  to  induction,  15. 
Magneto-motive,  12, 
Frogs,  378. 

GAUGE,  steam,  Standard,  185. 
Gear  journals,  Lubrication  of,  90. 
Gearing,  Efficiency  of,  220. 
Gearing,  Bevel,  403. 

Hydraulic,  83,  227. 

Worm,  222. 
Gears,  Beveled,  93. 
Spur,  87. 

with  "  staggered  "  teeth,  89. 
Governor  for  engines,  40. 
Guard  wires,  143,  379. 

HANGERS,  Span,  371. 

Guard  iron,  375. 
Heating  in  magnet  coils  or  armature,  198. 

of  bearings,  199. 
Horse-power,  44,  45. 

per  car,  171. 

INDICATOR  cards,  49,  51,  52,  53,  54. 

card  from  railway  power  station,  55. 
Indicators  for  engines,  46. 

Use  of,  47. 
Induction,  15. 

Total,  23. 

Inequality  of  work  between  two  motors,  80. 
Insulating  joint,  376. 
Insulator  clamps,  374. 

LAW,  Ohm's,  14. 
Lightning  arrester,  113,  185. 

arrester,  Diagram  of,  113. 


412  INDEX. 

Lightning  arrester,  Principles  of,  1 14. 

arrester,  Self-induction  coils  for,  390. 
arrester,  Westinghouse,  115. 
arrester,  Wirt,  115- 
Damage  done  by,  185. 
Protecting  dynamos  against,  391. 
Protecting  motors  against,  393. 
Life  of  motor  parts,  318. 
Line,  Construction  of,  369. 

Cost  of  maintenance  of,  318. 
Drop  of,  285. 
Efficiency  of,  216. 
Height  of,  378. 
Insulation  resistance  of,  216. 
resistance  of,  Calculation  of,  123. 

resistance  of,  Calculation  of,  with  "bunched"  cars,  140. 
Load,  Predetermination  of  maximum,  124. 
Ratio  of  maximum  and  average,  169. 
Locomotive,  electric,  Weight  efficiency  of  the,  281. 
Locomotives,  Cost  of  a  horse-power  in  steam  and  electric,  282. 
electric,  Repairs  of,  288. 
steam,  Repairs  of,  288. 
steam,  Weight  efficiency  of,  281. 

MAGNETIC  circuit,  Resistance  of  the,  322. 

properties  of  various  materials,  17. 
Magnetization,  Density  of,  17. 
Magnets,  Field,  9. 

McCluer  telephone  return  circuit,  365. 
Motive  power,  Cost  of,  by  steam  and  electricity,  293. 
Motor,  Action  of,  26. 

and  gearing,  Efficiency  of,  224. 

as  dynamo  on  down  grade,  248, 294. 

care  of,  Instructions  for,  116. 

Commercial  efficiency  of  a  single,  220. 

Drehstrom,  for  electric  traction,  263. 

equipment,  Cost  of,  311. 

equipment,  Cost  of  repairs  of,  318. 

gearless,  Conditions  for,  226. 

Maximum  rate  of  work  of  a,  69. 

Methods  of  suspension  for  the,  89. 

Regulation  of  a,  by  varying  its  field,  65. 

repairs,  316. 

Short  gearless,  96,  225. 

single-reduction  gear,  Efficiency  of,  222. 

speed,  Regulation  of,  by  varying  E.  \M.  F.,  70. 

truck,  Eickemeyer  gearless,  94. 

truck,  Rae,  93. 

Westinghouse  gearless,  96,  225. 
Motors  changed  from  series  to  multiple,  79. 

Commercial  efficiency  of  a  pair  of,  without  gear  loss,  220. 

Eickemeyer  gearless,  225. 

for  high-speed  service,  274,  298,  299,  300. 

gearless,  Conditions  for,  226. 

gearless,  Efficiency  of,  226. 

One  versus  two,  220. 


INDEX.  413 

Motors,  Practical  care  of,  116. 
Repairs  of,  316. 
Shunt  versus  series,  85,  866, , 
street-railway,  Sources  of  loss  in,  218. 
Typical  modern,  97-99. 

OHM'S  law,  14. 
Operation,  Cost  of,  258. 

as  percentage  of  gross  earnings,  326. 

PLANS  for  small  power  station,  174. 

for  power  station  of  moderate  size,  176. 

for  very  large  power  station,  178. 
Pole  clamps,  369. 

specifications,  379. 
Poles,  Cost  of,  310. 
Portelectric  system,  The,  269. 
Power,  Average,  171. 

plant,  Material  of,  175. 

plant,  Proper  capacity  of  a,  167. 

plant,  Rule  for  subdivision  of  a,  181. 

required  for  a  railway  system,  166. 

required  for  electric  cars  on  grades,  170,  171. 

required  for  hauling  one  ton  at  various  speeds,  277,  278,  279,  280. 

station,  Arrangement  of  a,  165,  184. 

station,  Cost  of,  312. 

station,  Efficiency  of,  at  various  loads,  214. 

station,  Locating  a,  162. 

station,  Position  of  a,  161. 

stations,  161. 

stations  of  various  capacities,  Cost  of  a  horse-power  hou,r  in,  284. 
Pressure,  Mean,  in  engine  cylinder,  45. 

mean,  Method  of  computing,  50. 

RAIL  sections,  150,  151. 

Railroading,  electric,  High-speed,  272. 

electric,  Limiting  possibilities  of,  275. 
high-speed  electric,  Resistance  to  motion  in,  276. 
Rails,  Bonding,  138. 

Detecting  trouble  in  connections  of,  139. 
Railway  crossings,  147. 

dynamos,  electromotive  force  of,  Danger  to  life  from,  123. 

Electric,  at  Richmond,  Va.,  350. 

electric,  Bentley  and  Knight's,  346. 

electric,  Bessolo,  Patent  involving  the,  338. 

electric,  Davenport's  experiments  on  the,  334. 

electric,  Farmer's  experiments  on  the,  336. 

electric,  Field's,  342. 

electric,  First  commercial,  343. 

electric,  Green's  experiments  on  the,  339. 

electric,  Henry's,  246. 

electric,  History  of,  333. 

electric,  Lilley  and  Colton's  experiments  on  the,  337. 

electric,  Page's  experiments  on  the,  335. 

electric,  Pinkus,  Patent  involving  the,  337. 


4 14  INDEX. 

Railway,  electric,  Sprague's  work  in  the,  349. 

electric,  Van  Depoele's,  349- 

statione  fficiency,  214. 
Railways,  electric,  Accounting  rules  for,  329. 

electric,  Cost  of  motive  power  for,  314. 

electric,  Gross  receipts  necessary  for,  322. 

electric,  Operating  expenses  of,  313. 

electric.  Patents  on,  351. 
Repair  shop,  1 54. 

shop,  Special  tools  for,  156. 

Resistance  of  rail  and  earth  return,  137.  •      .  '.,- 

of  iron  and  copper,  138. 
Specific,  14. 
Rheostat,  76. 
Rods,  Connecting,  instead  of  gears,  94. 

SECTION  hangers,  376. 
Series,  motors,  Connection  of,  in,  78. 
Series-multiple  control  of  motors,  403. 

Short-circuiting  versus  cutting  out  damaged  motor  armature  coil,  270. 
Snow,  General  treatment  of,  160. 
machines,  157. 
Removal  of,  157. 
Span  wires,  Stretching  of,  370. 
Splicing  gears,  376. 
Ste*am,  Absolute  pressure  of,  206. 

engine,  29. 

engine,  Condensing,  36. 

engine,  Losses  in  underloading  the,  39. 

engine,  Practical  efficiency  of  the,  210. 

engine,  Practical  results  from  the,  56. 

engine,  Throttling,  35. 

engine,  Working  of  a,  34. 

engines,  compound,  Economy  of,  207. 

engines,  Conditions  for  maximum  efficiency  of,  207. 

engines,  Friction  in,  203. 

engines  for  large  power  stations,  168. 

engines,  Kind  of,  suitable  for  given  plant,  169. 

engines,  Relation  between  maximum  and  average  load  of,  208. 

Most  economical  point  of  cut-off  of,  206. 

Most  economical  ratio  of  expansion  of,  206. 

plant  for  electric  railway,  Cost  of,  311. 

turbine,  Results  obtained  from  the,  215. 
Street-railway  service,  Variation  of,  with  size  of  city,  323. 
Strength  of  field  in  electric  motors,  65. 
Storage  battery  cars,  Regulation  of,  77. 
battery,  Definition  of,  230. 
battery,  Variations  of  capacity  in  a,  241. 
batteries,  Condition  of  electric  traction  by,  235. 
batteries,  Cost  of  maintenance  of,  250. 
batteries,  Grids  for,  236,  237. 

TELEPHONE  circuits,  Interference  of  railways  with,  143,  353,  355. 
Telpherage,  264. 

Electric  arrangements  of,  266. 


INDEX. 


4'5 


Testing  line,  Method  of,  405. 
Tolls,  328. 

Tonnage  coefficient,  178.  277. 
Track,  147.  ' ,' 

bonding,  Cost  of.  310 
Construction  of,  149. 
Cost  of  maintenance  of,  318. 
for  electric  railways,  Cost  of,  309. 
Traction  by  storage  batteries,  230. 
coefficient,  124. 
electric,  Actual  cost  of,  328. 
electric,  Alternating  currents  in,  261. 

electric,  by  storage  batteries,  Commercial  availability  of.  248 
electric,  Commercial  consideration  of,  309. 
electric,  Commercial  efficiency  of,  228. 
electric,  Efficiency  of,  202. 
electric,  High-speed  automatic,  268. 
electric,  high-speed  automatic,  Siemens',  343. 
electric,  high-speed,  Commercial  aspects  of,  305. 
electric,  high-speed,  Efficiency  of,  290. 
electric,  high-speed,  Experiments  on,  296. 
electric,  high-speed,  Limiting  curvatures  for,  304. 
electric,  high-speed,  Line  voltage  for,  304. 
electric,  high-speed,  Conclusions  regarding,  293. 
electric,  high-speed,  Power  required  for,  298. 
electric,  Probable  maximum  efficiency  of,  228. 
electric,  Three-rail  system  of,  254. 
electric,  Total  cost  per  car-mile  of,  320. 
electric,  Transmissions  and  transformations  in.  202. 
Trailers,  321. 

Trail-car-mile,  Cost  of,  321. 
Train  mile  versus  H.  P.  hour,  291. 
Transit,  Electric  rapid,  for  large  cities.  295. 
Trolley  spans,  370. 

system,  Single  versus  double,  142. 
wire,  369. 

wire,  Anchoring,  375. 
wire,  Arrangement  of,  on  curves,  373. 
wire  clamps,  371. 
wire,  Cost  of,  310. 
wire,  Location  of,  371. 
wire,  Running,  372. 
Trolleys,  107,377. 

and  bases,   1 10. 
Early  experiments  on,  347. 
Truck,  Maximum  traction,  105. 

Radial,  106. 
Trucks,  100. 
Turbines,  58. 
Typical  electric  railway.   101,  103. 

VALVE.  33. 

gear,  Corliss,  38. 

gears,  36. 
Voltage,  Danger  to  life  from,  123. 


416  INDEX. 

WATER  power,  163. 

power,  Difficulties  with,  163. 
Water-wheel,  Difficulty  of  governing,  61. 
Water-wheels,  57. 
Winding,  Compound,  12. 
Series,  12. 
Shunt,  12. 

Wire,  Supplementary,  139,  385. 
Wire-tie,  385. 
Wiring  line  distance  with  i-o  B.  &  S..  142. 

line,  Overhead  system  of,  137. 

Standard  car,  of  Edison  Co.,  109. 

Standard  car,  of  Thomson-Houston  Co..  109. 
Watt  meters,  315. 

meter,  L'se  of,  on  cars,  220. 


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